Method for decoding a video bitstream

ABSTRACT

A method for decoding a video bitstream comprising the steps of: receiving said video bitstream that includes a plurality of different layers, where one of said plurality of different layers includes a plurality of temporal sub-layers; receiving a value of a value attribute associated with one of the plurality of temporal sub-layers where said value includes a first part and a second part separated by a delimiter, decoding said bitstream based upon said value attribute.

CROSS-REFERENCE TO RELATED APPLICATIONS

None.

TECHNICAL FIELD

The present disclosure relates generally to electronic devices.

BACKGROUND ART

Electronic devices have become smaller and more powerful in order tomeet consumer needs arid to improve portability and convenience.Consumers have become dependent upon electronic devices and have come toexpect increased functionality. Some examples of electronic devicesinclude desktop computers, laptop computers, cellular phones, smartphones, media players, integrated circuits, etc.

Some electronic devices are used for processing and displaying digitalmedia. For example, portable electronic devices now allow for digitalmedia to be consumed at almost any location where a consumer may be.Furthermore, some electronic devices may provide download or streamingof digital media content for the use and enjoyment of a consumer.

The increasing popularity of digital media has presented severalproblems. For example, efficiently representing high-quality digitalmedia for storage, transmittal and rapid playback presents severalchallenges. As can be observed from this discussion, systems and methodsthat represent digital media efficiently with improved performance maybe beneficial.

The foregoing and other objectives, features, and advantages of theinvention will be more readily understood upon consideration of thefollowing detailed description of the invention, taken in conjunctionwith the accompanying drawings.

SUMMARY OF INVENTION

In order to solve the foregoing problem, a method for decoding a videobitstream comprising the steps of: (a) receiving said video bitstreamthat includes a plurality of different layers, where one of saidplurality of different layers includes a plurality of temporalsub-layers; (b) receiving a value of a value attribute associated withone of the plurality of temporal sub-layers where said value includes afirst part and a second part separated by a delimiter; (c) decoding saidbitstream based upon said value attribute, (d) wherein said first partis an 8-bit unsigned integer with a value equal to a level for temporalsub-layer zero of said plurality of temporal sub-layers, (e) whereinsaid second part is, alternatively, (i) if said second part is presentthen said second part is a coded string of a single layer video encodingwith a syntax element based upon a sub layer profile space, a sub layertier flag, a sub layer profile idc, 32 bits of sub layer profilecompatibility flags, and each of 6 bytes of constraint flags startingfrom a sub layer progressive source flag respectively substituted for anelement general profile space, a general tier flag, a general profileidc, a general profile compatibility flag in the range of 0 to 31,inclusive, and each of 6 bytes of constraint flags starting from ageneral progressive source flag, (ii) if said second part is absent thenall other profile tier level parameters for said temporal sub-layerzero, besides a sub layer level idc[0] parameter which is signaled insaid first part, are inferred to be same as the value of thoseparameters signaled codecs parameter for the representation, (f) whereinif all representations of an adaptation element contain temporalsub-layering with the same profile tier, level, and flag information forsaid temporal sub-layer zero then at least one of said first part andsaid second part may be used for said adaptation element.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1A is a block diagram illustrating an example of one or moreelectronic devices in which systems and methods for sending a messageand buffering a bitstream may be implemented.

FIG. 1B is another block diagram illustrating an example of one or moreelectronic devices in which systems and methods for sending a messageand buffering a bitstream may be implemented.

FIG. 2A is a block diagram illustrating one configuration of an encoder604 on an electronic device.

FIG. 2B is another block diagram illustrating one configuration of anencoder 604 on an electronic device.

FIG. 3A is a block diagram illustrating one configuration of a decoderon an electronic device.

FIG. 3B is another block diagram illustrating one configuration of adecoder on an electronic device.

FIG. 4 illustrates various components that may be utilized in atransmitting electronic device.

FIG. 5 is a block diagram illustrating various components that may beutilized in a receiving electronic device.

FIG. 6 is a block diagram illustrating one configuration of anelectronic device in which systems and methods for sending a message maybe implemented.

FIG. 7 is a block diagram illustrating one configuration of anelectronic device in which systems and methods for buffering a bitstreammay be implemented.

FIG. 8A illustrates different NAL Unit header syntax.

FIG. 8B illustrates different NAL Unit header syntax.

FIG. 8C illustrates different NAL Unit header syntax.

FIG. 9 illustrates a general NAL Unit syntax.

FIG. 10 illustrates an existing video parameter set.

FIG. 11 illustrates existing scalability types.

FIG. 12 illustrates a base layer and enhancement layers.

FIG. 13 illustrates an exemplary picture having multiple slices.

FIG. 14 illustrates another exemplary picture having multiple slices.

FIG. 15 illustrates a picture with column and row boundaries.

FIG. 16 illustrates a picture with slices.

FIG. 17 illustrates an access unit with a base layer, enhancementlayers, and tiles.

FIG. 18A illustrates an exemplary slide segment header syntax.

FIG. 18B illustrates an exemplary slide segment header syntax.

FIG. 18C illustrates an exemplary slide segment header syntax.

FIG. 18D illustrates an exemplary slide segment header syntax.

FIG. 19 illustrates a base layer and enhancement layers.

FIG. 20A illustrates an exemplary video parameter set (vps) extensionsyntax.

FIG. 20B illustrates an exemplary video parameter set (vps) extensionsyntax.

FIG. 21 illustrates an exemplary representation format syntax.

FIG. 22 illustrates an exemplary vps video usability information (VUI)syntax.

FIG. 23 illustrates an exemplary vps video usability information (VUI)syntax.

FIG. 24A illustrates an exemplary video parameter set (VPS) syntax.

FIG. 24B illustrates an exemplary video parameter set (VPS) syntax.

FIG. 24C illustrates an exemplary video parameter set (VPS) syntax.

FIG. 25A illustrates an exemplary vps extension syntax.

FIG. 25B illustrates an exemplary vps extension syntax.

FIG. 25C illustrates an exemplary vps extension syntax.

FIG. 26A illustrates an exemplary vps video usability information (VUI)syntax.

FIG. 26B illustrates an exemplary vps video usability information (VUI)syntax.

FIG. 27A illustrates an exemplary sequence parameter set (SPS) extensionsyntax.

FIG. 27B illustrates an exemplary sequence parameter set (SPS) extensionsyntax.

FIG. 28A illustrates an exemplary sps video usability information (SPSVUI).

FIG. 28B illustrates an exemplary sps video usability information (SPSVUI).

FIG. 29 illustrates an exemplary profile_tier_level syntax.

FIG. 30 illustrates an exemplary profile_tier_level syntax.

DESCRIPTION OF EMBODIMENTS

FIG. 1A is a block diagram illustrating an example of one or moreelectronic devices 102 in which systems and methods for sending amessage and buffering a bitstream may be implemented. In this example,electronic device A 102 a and electronic device B 102 b are illustrated.However, it should be noted that one or more of the features andfunctionality described in relation to electronic device A 102 a andelectronic device B 102 b may be combined into a single electronicdevice in some configurations.

Electronic device A 102 a includes an encoder 104. The encoder 104includes a message generation module 108. Each of the elements includedwithin electronic device A 102 a (e.g., the encoder 104 and the messagegeneration module 108) may be implemented in hardware, software or acombination of both.

Electronic device A 102 a may obtain one or more input pictures 106. Insome configurations, the input picture(s) 106 may be captured onelectronic device A 102 a using an image sensor, may be retrieved frommemory and/or may be received from another electronic device.

The encoder 104 may encode the input picture(s) 106 to produce encodeddata. For example, the encoder 104 may encode a series of input pictures106 (e.g., video). In one configuration, the encoder 104 may be a HEVCencoder. The encoded data may be digital data (e.g., part of a bitstream114). The encoder 104 may generate overhead signaling based on the inputsignal.

The message generation module 108 may generate one or more messages. Forexample, the message generation module 108 may generate one or moresupplemental enhancement information (SEI) messages or other messages.For a CPB that supports operation on a sub-picture level, the electronicdevice 102 may send sub-picture parameters, (e.g., CPB removal delayparameter). Specifically, the electronic device 102 (e.g., the encoder104) may determine whether to include a common decoding unit CPB removaldelay parameter in a picture timing SEI message. For example, theelectronic device may set a flag (e.g.,common_du_cpb_removal_delay_flag) to one when the encoder 104 isincluding a common decoding unit CPB removal delay parameter (e.g.,common_du_cpb_removal_delay) in the picture timing SEI message. When thecommon decoding unit CPB removal delay parameter is included, theelectronic device may generate the common decoding unit CPB removaldelay parameter that is applicable to all decoding units in an accessunit. In other words, rather than including a decoding unit CPB removaldelay parameter for each decoding unit in an access unit, a commonparameter may apply to all decoding units in the access unit with whichthe picture timing SEI message is associated.

In contrast, when the common decoding unit CPB removal delay parameteris not to be included in the picture timing SEI message, the electronicdevice 102 may generate a separate decoding unit CPB removal delay foreach decoding unit in the access unit with which the picture tinning SEImessage is associated. In some configurations, electronic device A 102 amay send the message to electronic device B 102 b as part of thebitstream 114. In some configurations electronic device A 102 a may sendthe message to electronic device B 102 b by a separate transmission 110.For example, the separate transmission may not be part of the bitstream114. For instance, a picture timing SEI message or other message may besent using some out-of-band mechanism. It should be noted that, in someconfigurations, the other message may include one or more of thefeatures of a picture timing SEI message described above. Furthermore,the other message, in one or more aspects, may be utilized similarly tothe SEI message described above.

The encoder 104 (and message generation module 108, for example) mayproduce a bitstream 114. The bitstream 114 may include encoded picturedata based on the input picture(s) 106. In some configurations, thebitstream 114 may also include overhead data, such as a picture timingSEI message or other message, slice header(s), PPS(s), etc. Asadditional input pictures 106 are encoded, the bitstream 114 may includeone or more encoded pictures. For instance, the bitstream 114 mayinclude one or more encoded pictures with corresponding overhead data(e.g., a picture timing SEI message or other message).

The bitstream 114 may be provided to a decoder 112. In one example, thebitstream 114 may be transmitted to electronic device B 102 b using awired or wireless link. In some cases, this may be done over a network,such as the Internet or a Local Area Network (LAN). As illustrated inFIG. 1A, the decoder 112 may be implemented on electronic device B 102 bseparately from the encoder 104 on electronic device A 102 a. However,it should be noted that the encoder 104 and decoder 112 may beimplemented on the same electronic device in some configurations. In animplementation where the encoder 104 and decoder 112 are implemented onthe same electronic device, for instance, the bitstream 114 may beprovided over a bus to the decoder 112 or stored in memory for retrievalby the decoder 112.

The decoder 112 may be implemented in hardware, software or acombination of both. In one configuration, the decoder 112 may be a HEVCdecoder. The decoder 112 may receive (e.g., obtain) the bitstream 114.The decoder 112 may generate one or more decoded pictures 118 based onthe bitstream 114. The decoded picture(s) 118 may be displayed, playedback, stored in memory and/or transmitted to another device, etc.

The decoder 112 may include a CPB 120. The CPB 120 may temporarily storeencoded pictures. The CPB 120 may use parameters found in a picturetiming SEI message to determine when to remove data. When the CPB 120supports operation on a sub-picture level, individual decoding units maybe removed rather than entire access units at one time. The decoder 112may include a Decoded Picture Buffer (DPB) 122. Each decoded picture isplaced in the DPB 122 for being referenced by the decoding process aswell as for output and cropping. A decoded picture is removed from theDPB at the later of the DPB output time or the time that it becomes nolonger needed for inter-prediction reference.

The decoder 112 may receive a message (e.g., picture timing SEI messageor other message). The decoder 112 may also determine whether thereceived message includes a common decoding unit CPB removal delayparameter (e.g., common_du_cpb_removal_delay). This may includeidentifying a flag (e.g., common_du_cpb_removal_delay_flag) that is setwhen the common parameter is present in the picture timing SEI message.If the common parameter is present, the decoder 112 may determine thecommon decoding unit CPB removal delay parameter applicable to alldecoding units in the access unit. If the common parameter is notpresent, the decoder 112 may determine a separate decoding unit CPBremoval delay parameter for each decoding unit in the access unit. Thedecoder 112 may also remove decoding units from the CPB 120 using eitherthe common decoding unit CPB removal delay parameter or the separatedecoding unit CPB removal delay parameters.

The HRD described above may be one example of the decoder 112illustrated in FIG. 1A. Thus, an electronic device 102 may operate inaccordance with the HRD and CPB 120 and DPB 122 described above, in someconfigurations.

It should be noted that one or more of the elements or parts thereofincluded in the electronic device(s) 102 may be implemented in hardware.For example, one or more of these elements or parts thereof may beimplemented as a chip, circuitry or hardware components, etc. It shouldalso be noted that one or more of the functions or methods describedherein may be implemented in and/or performed using hardware. Forexample, one or more of the methods described herein may be implementedin and/or realized using a chipset, an Application-Specific IntegratedCircuit (ASIC), a Large-Scale Integrated circuit (LSI) or integratedcircuit, etc.

FIG. 1B is a block diagram illustrating another example of an encoder1908 and a decoder 1972. In this example, electronic device A 1902 andelectronic device B 1970 are illustrated. However, it should be notedthat the features and functionality described in relation to electronicdevice A 1902 and electronic device B 1970 may be combined into a singleelectronic device in some configurations.

Electronic device A 1902 includes the encoder 1908. The encoder 1908 mayinclude a base layer encoder 1910 and an enhancement layer encoder 1920.The encoder 1908 is suitable for scalable video coding and multi-viewvideo coding, as described later. The encoder 1908 may be implemented inhardware, software or a combination of both. In one configuration, theencoder 1908 may be a high-efficiency video coding (HEVC) coder,including scalable and/or multi-view. Other coders may likewise be used.Electronic device A 1902 may obtain a source 1906. In someconfigurations, the source 1906 may be captured on electronic device A1902 using an image sensor, retrieved from memory or received fromanother electronic device.

The encoder 1908 may code the source 1906 to produce a base layerbitstream 1934 and an enhancement layer bitstream 1936. For example, theencoder 1908 may code a series of pictures (e.g., video) in the source1906. In particular, for scalable video encoding for SNR scalabilityalso known as quality scalability the same source 1906 may be providedto the base layer and the enhancement layer encoder. In particular, forscalable video encoding for spatial scalability a downsampled source maybe used for the base layer encoder. In particular, for multi-viewencoding a different view source may be used for the base layer encoderand the enhancement layer encoder. The encoder 1908 may be similar tothe video encoder 1782 described later in connection with FIG. 2B.

The base layer bitstream 1934 and/or enhancement layer bitstream 1936may include coded picture data based on the source 1906. In someconfigurations, the base layer bitstream 1934 and/or enhancement layerbitstream 1936 may also include overhead data, such as slice headerinformation, PPS information, etc. As additional pictures in the source1906 are coded, the base layer bitstream 1934 and/or enhancement layerbitstream 1936 may include one or more coded pictures.

The base layer bitstream 1934 and/or enhancement layer bitstream 1936may be provided to the decoder 1972. The decoder 1972 may include a baselayer decoder 1980 and an enhancement layer decoder 1990. The videodecoder 1972 is suitable for scalable video decoding and multi-viewvideo decoding. In one example, the base layer bitstream 1934 and/orenhancement layer bitstream 1936 may be transmitted to electronic deviceB 1970 using a wired or wireless link. In some cases, this may be doneover a network, such as the Internet or a Local Area Network (LAN). Asillustrated in FIG. 1B, the decoder 1972 may be implemented onelectronic device B 1970 separately from the encoder 1908 on electronicdevice A 1902. However, it should be noted that the encoder 1908 anddecoder 1972 may be implemented on the same electronic device in someconfigurations. In an implementation where the encoder 1908 and decoder1972 are implemented on the same electronic device, for instance, thebase layer bitstream 1934 and/or enhancement layer bitstream 1936 may beprovided over a bus to the decoder 1972 or stored in memory forretrieval by the decoder 1972. The decoder 1972 may provide a decodedbase layer 1992 and decoded enhancement layer picture(s) 1994 as output.

The decoder 1972 may be implemented in hardware, software or acombination of both. In one configuration, the decoder 1972 may be ahigh-efficiency video coding (HEVC) decoder, including scalable and/ormulti-view. Other decoders may likewise be used. The decoder 1972 may besimilar to the video decoder 1812 described later in connection withFIG. 3B. Also, the base layer encoder and/or the enhancement layerencoder may each include a message generation module, such as thatdescribed in relation to FIG. 1A. Also, the base layer decoder and/orthe enhancement layer decoder may include a coded picture buffer and/ora decoded picture buffer, such as that described in relation to FIG. 1A.In addition, the electronic devices of FIG. 1B may operate in accordancewith the functions of the electronic devices of FIG. 1A, as applicable.

FIG. 2A is a block diagram illustrating one configuration of an encoder604 on an electronic device 602. It should be noted that one or more ofthe elements illustrated as included within the electronic device 602may be implemented in hardware, software or a combination of both. Forexample, the electronic device 602 includes an encoder 604, which may beimplemented in hardware, software or a combination of both. Forinstance, the encoder 604 may be implemented as a circuit, integratedcircuit, application-specific integrated circuit (ASIC), processor inelectronic communication with memory with executable instructions,firmware, field-programmable gate array (FPGA), etc., or a combinationthereof. In some configurations, the encoder 604 may be a HEVC coder.

The electronic device 602 may include a source 622. The source 622 mayprovide picture or image data (e.g., video) as one or more inputpictures 606 to the encoder 604. Examples of the source 622 may includeimage sensors, memory, communication interfaces, network interfaces,wireless receivers, ports, etc.

One or more input pictures 606 may be provided to an intra-frameprediction module and reconstruction buffer 624. An input picture 606may also be provided to a motion estimation and motion compensationmodule 646 and to a subtraction module 628.

The intra-frame prediction module and reconstruction buffer 624 maygenerate intra mode information 640 and an intra signal 626 based on oneor snore input pictures 606 and reconstructed data 660. The motionestimation and motion compensation module 646 may generate inter modeinformation 648 and an inter signal 644 based on one or more inputpictures 606 and a reference picture 678 from decoded picture buffer676. In some configurations, the decoded picture buffer 676 may includedata from one or more reference pictures in the decoded picture buffer676.

The encoder 604 may select between the intra signal 626 and the intersignal 644 in accordance with a mode. The intra signal 626 may be usedin order to exploit spatial characteristics within a picture in anintra-coding mode. The inter signal 644 may be used in order to exploittemporal characteristics between pictures in an inter coding mode. Whilein the intra coding mode, the intra signal 626 may be provided to thesubtraction module 628 and the intra mode information 640 may beprovided to an entropy coding module 642. While in the inter codingmode, the inter signal 644 may be provided to the subtraction module 628and the inter mode information 648 may be provided to the entropy codingmodule 642.

Either the intra signal 626 or the inter signal 644 (depending on themode) is subtracted from an input picture 606 at the subtraction module628 in order to produce a prediction residual 630. The predictionresidual 630 is provided to a transformation module 632. Thetransformation module 632 may compress the prediction residual 630 toproduce a transformed signal 634 that is provided to a quantizationmodule 636. The quantization module 636 quantizes the transformed signal634 to produce transformed and quantized coefficients (TQCs) 638.

The TQCs 638 are provided to an entropy coding module 642 and an inversequantization module 650. The inverse quantization module 650 performsinverse quantization on the TQCs 638 to produce an inverse quantizedsignal 652 that is provided to an inverse transformation module 654. Theinverse transformation module 654 decompresses the inverse quantizedsignal 652 to produce a decompressed signal 656 that is provided to areconstruction module 658.

The reconstruction module 658 may produce reconstructed data 660 basedon the decompressed signal 656. For example, the reconstruction module658 may reconstruct (modified) pictures. The reconstructed data 660 maybe provided to a deblocking filter 662 and to the intra predictionmodule and reconstruction butler 624. The deblocking filter 662 mayproduce a filtered signal 664 based on the reconstructed data 660.

The filtered signal 664 may be provided to a sample adaptive offset(SAO) module 666. The SAO module 666 may produce SAO information 668that is provided to the entropy coding module 642 and an SAO signal 670that is provided to an adaptive loop filter (ALF) 672. The ALF 672produces an ALF signal 674 that is provided to the decoded picturebuffer 676. The ALF signal 674 may include data from one or morepictures that may be used as reference pictures.

The entropy coding module 642 may code the TQCs 638 to produce bitstreamA 614 a (e.g., encoded picture data). For example, the entropy codingmodule 642 may code the TQCs 638 using Context-Adaptive Variable LengthCoding (CAVLC) or Context-Adaptive Binary Arithmetic Coding (CABAC). Inparticular, the entropy coding module 642 may code the TQCs 638 based onone or more of intra mode information 640, inter mode information 648and SAO information 668. Bitstream A 614 a (e.g., encoded picture data)may be provided to a message generation module 608. The messagegeneration module 608 may be configured similarly to the messagegeneration module 108 described in connection with FIG. 1. For example,the message generation module 608 may generate a message (e.g., picturetiming SEI message or other message) including sub-picture parameters.The sub-picture parameters may include one or more removal delays fordecoding units (e.g., common_du_cpb_removal_delay ordu_cpb_removal_delay[i]) and one or more NAL parameters (e.g.,common_num_nalus_in_du_minus1 or num_nalus_in_du_minus1[i]). In someconfigurations, the message may be inserted into bitstream A 614 a toproduce bitstream B 614 b. Thus, the message may be generated after theentire bitstream A 614 a is generated (e.g., after most of bitstream B614 b is generated), for example. In other configurations, the messagemay not be inserted into bitstream A 614 a (in which case bitstream B614 b may be the same as bitstream A 614 a), but may be provided in aseparate transmission 610.

In some configurations, the electronic device 602 sends the bitstream614 to another electronic device. For example, the bitstream 614 may beprovided to a communication interface, network interface, wirelesstransmitter, port, etc. For instance, the bitstream 614 may betransmitted to another electronic device via LAN, the Internet, acellular phone base station, etc. The bitstream 614 may additionally oralternatively be stored in memory or other component on the electronicdevice 602.

FIG. 2B is a block diagram illustrating one configuration of a videoencoder 1782 on an electronic device 1702. The video encoder 1782 mayinclude an enhancement layer encoder 1706, a base layer encoder 1709, aresolution upscaling block 1770 and an output interface 1780. The videoencoder of FIG. 2B, for example, is suitable for scalable video codingand multi-view video coding, as described herein.

The enhancement layer encoder 1706 may include a video input 1781 thatreceives an input picture 1704. The output of the video input 1781 maybe provided to an adder/subtractor 1783 that receives an output of aprediction selection 1750. The output of the adder/subtractor 1783 maybe provided to a transform and quantize block 1752. The output of thetransform and quantize block 1752 may be provided to an entropy encoding1748 block and a scaling and inverse transform block 1772. After entropyencoding 1748 is performed, the output of the entropy encoding block1748 may be provided to the output interface 1780. The output interface1780 may output both the encoded base layer video bitstream 1707 and theencoded enhancement layer video bitstream 1710.

The output of the scaling and inverse transform block 1772 may beprovided to an adder 1779. The adder 1779 may also receive the output ofthe prediction selection 1750. The output of the adder 1779 may beprovided to a deblocking block 1751. The output of the deblocking block1751 may be provided to a reference buffer 1794. An output of thereference buffer 1794 may be provided to a motion compensation block1754. The output of the motion compensation block 1754 may be providedto the prediction selection 1750. An output of the reference buffer 1794may also be provided to an intra predictor 1756. The output of the intrapredictor 1756 may be provided to the prediction selection 1750. Theprediction selection 1750 may also receive an output of the resolutionupscaling block 1770.

The base layer encoder 1709 may include a video input 1762 that receivesa downsampled input picture, or other image content suitable for combingwith another image, or an alternative view input picture or the sameinput picture 1703 (i.e., the same as the input picture 1704 received bythe enhancement layer encoder 1706). The output of the video input 1762may be provided to an encoding prediction loop 1764. Entropy encoding1766 may be provided on the output of the encoding prediction loop 1764.The output of the encoding prediction loop 1764 may also be provided toa reference buffer 1768. The reference buffer 1768 may provide feedbackto the encoding prediction loop 1764. The output of the reference buffer1768 may also be provided to the resolution upscaling block 1770. Onceentropy encoding 1766 has been performed, the output may be provided tothe output interface 1780. The encoded base layer video bitstream 1707and/or the encoded enhancement layer video bitstream 1710 may beprovided to one or more message generation modules, as desired.

FIG. 3A is a block diagram illustrating one configuration of a decoder712 on an electronic device 702. The decoder 712 may be included in anelectronic device 702. For example, the decoder 712 may be a HEVCdecoder. The decoder 712 and one or more of the elements illustrated asincluded in the decoder 712 may be implemented in hardware, software ora combination of both. The decoder 712 may receive a bitstream 714(e.g., one or more encoded pictures and overhead data included in thebitstream 714) for decoding. In some configurations, the receivedbitstream 714 may include received overhead data, such as a message(e.g., picture timing SEI message or other message), slice header, PPS,etc. In some configurations, the decoder 712 may additionally receive aseparate transmission 710. The separate transmission 710 may include amessage (e.g., a picture timing SEI message or other message). Forexample, a picture timing SEI message or other message may be receivedin a separate transmission 710 instead of in the bitstream 714. However,it should be noted that the separate transmission 710 may be optionaland may not be utilized in some configurations.

The decoder 712 includes a CPB 720. The CPB 720 may be configuredsimilarly to the CPB 120 described in connection with FIG. 1 above. Thedecoder 712 may receive a message (e.g., picture timing SEI message orother message) with sub-picture parameters and remove and decodedecoding units in an access unit based on the sub-picture parameters. Itshould be noted that one or more access units may be included in thebitstream and may include one or more of encoded picture data andoverhead data.

The Coded Picture Buffer (CPB) 720 may provide encoded picture data toan entropy decoding module 701. The encoded picture data may be entropydecoded by an entropy decoding module 701, thereby producing a motioninformation signal 703 and quantized, scaled and/or transformedcoefficients 705.

The motion information signal 703 may be combined with a portion of areference frame signal 798 from a decoded picture buffer 709 at a motioncompensation module 780, which may produce an inter-frame predictionsignal 782. The quantized, descaled and/or transformed coefficients 705may be inverse quantized, scaled and inverse transformed by an inversemodule 707, thereby producing a decoded residual signal 784. The decodedresidual signal 784 may be added to a prediction signal 792 to produce acombined signal 786. The prediction signal 792 may be a signal selectedfrom either the inter-frame prediction signal 782 produced by the motioncompensation module 780 or an intra-frame prediction signal 790 producedby an intra-frame prediction module 788. In some configurations, thissignal selection may be based on (e,g., controlled by) the bitstream714.

The intra-frame prediction signal 790 may be predicted from previouslydecoded information from the combined signal 786 (in the current frame,for example). The combined signal 786 may also be filtered by ade-blocking filter 794. The resulting filtered signal 796 may be writtento decoded picture buffer 709. The resulting filtered signal 796 mayinclude a decoded picture. The decoded picture buffer 709 may provide adecoded picture which may be outputted 718. In some cases decodedpicture buffer 709 may be a considered as frame memory.

FIG. 3B is a block diagram illustrating one configuration of a videodecoder 1812 on an electronic device 1802. The video decoder 1812 mayinclude an enhancement layer decoder 1815 and a base layer decoder 1813.The video decoder 812 may also include an interface 1889 and resolutionupscaling 1870. The video decoder of FIG. 3B, for example, is suitablefor scalable video coding and multi-view video encoded, as describedherein.

The interface 1889 may receive an encoded video stream 1885. The encodedvideo stream 1885 may consist of base layer encoded video stream andenhancement layer encoded video stream. These two streams may be sentseparately or together. The interface 1889 may provide some or all ofthe encoded video stream 1885 to an entropy decoding block 1886 in thebase layer decoder 1813. The output of the entropy decoding block 1886may be provided to a decoding prediction loop 1887. The output of thedecoding prediction loop 1887 may be provided to a reference buffer1888. The reference buffer may provide feedback to the decodingprediction loop 1887. The reference buffer 1888 may also output thedecoded base layer video stream 1884.

The interface 1889 may also provide some or all of the encoded videostream 1885 to an entropy decoding block 1890 in the enhancement layerdecoder 1815. The output of the entropy decoding block 1890 may beprovided to an inverse quantization block 1891. The output of theinverse quantization block 1891 may be provided to an adder 1892. Theadder 1892 may add the output of the inverse quantization block 1891 andthe output of a prediction selection block 1895. The output of the adder1892 may be provided to a deblocking block 1893. The output of thedeblocking block 1893 may he provided to a reference buffer 1894. Thereference buffer 1894 may output the decoded enhancement layer videostream 1882. The output of the reference buffer 1894 may also beprovided to an intra predictor 1897. The enhancement layer decoder 1815may include motion compensation 1896. The motion compensation 1896 maybe performed after the resolution upscaling 1870. The predictionselection block 1895 may receive the output of the intra predictor 1897and the output of the motion compensation 1896. Also, the decoder mayinclude one or more coded picture buffers, as desired, such as togetherwith the interface 1889.

FIG. 4 illustrates various components that may be utilized in atransmitting electronic device 802. One or more of the electronicdevices 102, 602, 702 described herein may be implemented in accordancewith the transmitting electronic device 802 illustrated in FIG. 4.

The transmitting electronic device 802 includes a processor 817 thatcontrols operation of the electronic device 802. The processor 817 mayalso be referred to as a CPU. Memory 811, which may include bothread-only memory (ROM), random access memory (RAM) or any type of devicethat may store information, provides instructions 813 a (e.g.,executable instructions) and data 815 a to the processor 817. A portionof the memory 811 may also include non-volatile random access memory(NVRAM). The memory 811 may be in electronic communication with theprocessor 817.

Instructions 813 b and data 815 b may also reside in the processor 817.Instructions 813 b and/or data 815 b loaded into the processor 817 mayalso include instructions 813 a and/or data 815 a from memory 811 thatwere loaded for execution or processing by the processor 817. Theinstructions 813 b may be executed by the processor 817 to implement thesystems and methods disclosed herein. For example, the instructions 813b may be executable to perform one or more of the methods 200, 300, 400,500 described above.

The transmitting electronic device 802 may include one or morecommunication interfaces 819 for communicating with other electronicdevices receiving electronic device). The communication interfaces 819may be based on wired communication technology, wireless communicationtechnology, or both. Examples of a communication interface 819 include aserial port, a parallel port, a Universal Serial Bus (USB), an Ethernetadapter, an IEEE 1394 bus interface, a small computer system interface(SCSI) bus interface, an infrared (IR) communication port, a Bluetoothwireless communication adapter, a wireless transceiver in accordancewith 3rd Generation Partnership Project (3GPP) specifications and soforth.

The transmitting electronic device 802 may include one or more outputdevices 823 and one or more input devices 821. Examples of outputdevices 823 include a speaker, printer, etc. One type of output devicethat may be included in an electronic device 802 is a display device825. Display devices 825 used with configurations disclosed herein mayutilize any suitable image projection technology, such as a cathode raytube (CRT), liquid crystal display (LCD), light-emitting diode (LED),gas plasma, electroluminescence or the like. A display controller 827may be provided for converting data stored in the memory 811 into text,graphics, and/or moving images (as appropriate) shown on the displaydevice 825. Examples of input devices 821 include a keyboard, mouse,microphone, remote control device, button, joystick, trackball,touchpad, touchscreen, lightpen, etc.

The various components of the transmitting electronic device 802 arecoupled together by a bus system 829, which may include a power bus, acontrol signal bus and a status signal bus, in addition to a data bus.However, for the sake of clarity, the various buses are illustrated inFIG. 4 as the bus system 829. The transmitting electronic device 802illustrated in FIG. 4 is a functional block diagram rather than alisting of specific components.

FIG. 5 is a block diagram illustrating various components that may beutilized in a receiving electronic device 902. One or more of theelectronic devices 102, 602, 702 described herein may be implemented inaccordance with the receiving electronic device 902 illustrated in FIG.5.

The receiving electronic device 902 includes a processor 917 thatcontrols operation of the electronic device 902. The processor 917 mayalso be referred to as a CPU. Memory 911, which may include bothread-only memory (ROM), random access memory (RAM) or any type of devicethat may store information, provides instructions 913 a (e.g.,executable instructions) and data 915 a to the processor 917. A portionof the memory 911 may also include non-volatile random access memory(NVRAM). The memory 911 may be in electronic communication with theprocessor 917.

Instructions 913 b and data 915 b may also reside in the processor 917.Instructions 913 b and/or data 915 b loaded into the processor 917 mayalso include instructions 913 a and/or data 915 a from memory 911 thatwere loaded for execution or processing by the processor 917. Theinstructions 913 b may be executed by the processor 917 to implement thesystems and methods disclosed herein. For example, the instructions 913b may be executable to perform one or more of the methods 200, 300, 400,500 described above.

The receiving electronic device 902 may include one or morecommunication interfaces 919 for communicating with other electronicdevices (e.g., a transmitting electronic device). The communicationinterface 919 may be based on wired communication technology, wirelesscommunication technology, or both. Examples of a communication interface919 include a serial port, a parallel port, a Universal Serial Bus(USB), an Ethernet adapter, an IEEE 1394 bus interface, a small computersystem interface (SCSI) bus interface, an infrared (IR) communicationport, a Bluetooth wireless communication adapter, a wireless transceiverin accordance with 3rd Generation Partnership Project (3GPP)specifications and so forth.

The receiving electronic device 902 may include one or more outputdevices 923 and one or more input devices 921. Examples of outputdevices 923 include a speaker, printer, etc. One type of output devicethat may be included in an electronic device 902 is a display device925. Display devices 925 used with configurations disclosed herein mayutilize any suitable image projection technology, such as a cathode raytube (CRT), liquid crystal display (LCD), light-emitting diode (LED),gas plasma, electroluminescence or the like. A display controller 927may be provided for converting data stored in the memory 911 into text,graphics, and/or moving images (as appropriate) shown on the displaydevice 925. Examples of input devices 921 include a keyboard, mouse,microphone, remote control device, button, joystick, trackball,touchpad, touchscreen, lightpen, etc.

The various components of the receiving electronic device 902 arecoupled together by a bus system 929, which may include a power bus, acontrol signal bus and a status signal bus, in addition to a data bus.However, for the sake of clarity, the various buses are illustrated inFIG. 5 as the bus system 929. The receiving electronic device 902illustrated in FIG. 5 is a functional block diagram rather than alisting of specific components.

FIG. 6 is a block diagram illustrating one configuration of anelectronic device 1002 in which systems and methods for sending amessage may be implemented. The electronic device 1002 includes encodingmeans 1031 and transmitting means 1033. The encoding means 1031 andtransmitting means 1033 may generate a bitstream 1014. FIG. 4 aboveillustrates one example of a concrete apparatus structure of FIG. 6. ADigital Signal Processor (DSP) May be realized by software.

FIG. 7 is a block diagram illustrating one configuration of anelectronic device 1102 in which systems and methods for buffering abitstream 1114 may be implemented. The electronic device 1102 mayinclude receiving means 1135 and decoding means 1137. The receivingmeans 1135 and decoding means 1137 may receive a bitstream 1114. FIG. 5above illustrates one example of a concrete apparatus structure of FIG.7. A DSP may be realized by software.

The decoding process for reference picture set (RPS) may be invoked.Reference picture set is a set of reference pictures associated with apicture, consisting of all reference pictures that are prior to theassociated picture in decoding order, that may be used for interprediction of the associated picture or any picture following theassociated picture in decoding order.

The bitstream of the video may include a syntax structure that is placedinto logical data packets generally referred to as Network AbstractionLayer (NAL) units. Each NAL unit includes a NAL unit header, such as atwo-byte NAL unit header (e.g., 16 bits), to identify the purpose of theassociated data payload. For example, each coded slice (and/or picture)may be coded in one or more slice (and/or picture) NAL units. Other NALunits may be included for other categories of data, such as for example,supplemental enhancement information, coded slice of temporal sub-layeraccess (TSA) picture, coded slice of step-wise temporal sub-layer access(STSA) picture, coded slice a non-TSA, non-STSA trailing picture, codedslice of broken link access picture, coded slice of instantaneousdecoded refresh picture, coded slice of clean random access picture,coded slice of decodable leading picture, coded slice of tagged fordiscard picture, video parameter set, sequence parameter set, pictureparameter set, access unit delimiter, end of sequence, end of bitstream,filler data, and/or sequence enhancement information message. Table (1)illustrates one example of NAL unit codes and NAL unit type classes.Other NAL unit types may be included, as desired. It should also beunderstood that the NAL unit type values for the NAL units shown in theTable (1) may be reshuffled and reassigned. Also additional NAL unittypes may be added. Also some NAL unit types may be removed.

An intra random access point (IRAP) picture is a coded picture for whicheach video coding layer NAL unit has nal_unit_type in the range ofBLA_W_LP to RSV IRAP VCL23, inclusive as shown in Table (1). An IRAPpicture contains only Intra coded (I) slices. An instantaneous decodingrefresh (IDR) picture is an IRAP picture for which each video codinglayer NAL unit has nal_unit_type equal to IDR_W_RADL or IDR_N_LP asshown in Table 14). An instantaneous decoding refresh (IDR) picturecontains only I slices, and may be the first picture in the bitstream indecoding order, or may appear later in the bitstream. Each IDR pictureis the first picture of a coded video sequence (CVS) in decoding order.A broken link access (BLA) picture is an IRAP picture for which eachvideo coding layer NAL unit has nal_unit_type equal to BLA_W_LP,BLA_W_RADL, or BLA_N_LP as shown in Table (1). A BLA picture containsonly I slices, and may be the first picture in the bitstream in decodingorder, or may appear later in the bitstream. Each BLA picture begins anew coded video sequence, and has the same effect on the decodingprocess as an IDR picture. However, a BLA picture contains syntaxelements that specify a non-empty reference picture set. Clean randomaccess (CRA) access unit is an access unit in which the coded picture isa CRA picture. Clean random access (CRA) picture is an IRAP picture forwhich each VCL NAL unit has nal_unit_type equal to CRA_NUT as shown inTable (1). A CRA picture contains only I slices, and may be the firstpicture in the bitstream in decoding order, or may appear later in thebitstream. A CRA picture may have associated RADL or RASL pictures. Whena CRA picture has NoRaslOutputFlag equal to 1, the associated RASLpictures are not output by the decoder, because they may not bedecodable, as they may contain references to pictures that are notpresent in the bitstream.

Coded video sequence (CVS) may be a sequence of access units thatconsists, in decoding order, of an IRAP access unit withNoRaslOutputFlag equal to 1, followed by zero or more access units thatare not IRAP access units with NoRaslOutputFlag equal to 1, includingall subsequent access units up to but not including any subsequentaccess unit that is an IRAP access unit with NoRaslOutputFlag equal to1.

TABLE 1 Name of Content of NAL unit and raw byte sequence NAL unitnal_unit_type nal_unit_type payload (RBSP) syntax structure type class 0TRAIL_N Coded slice segment of a non-TSA, Video Coding 1 TRAIL_Rnon-STSA trailing picture Layer (VCL) sIice_segment_layer_rbsp( ) 2TSA_N Coded slice segment of a temporal VCL 3 TSA_R sub-layer access(TSA) picture slice_segment_layer_rbsp( ) 4 STSA_N Coded slice segmentof an Step- VCL 5 STSA_R wise Temporal sub-layer access (STSA) pictureslice_segment_Iayer_rbsp( ) 6 RADL_N Coded slice segment of a random VCL7 RADL_R access decodable leading (RADL) pictureslice_segment_layer_rbsp( ) 8 RASL_N Coded slice segment of a random VCL9 RASL_R access skipped leading (RASL) picture slice_segment_ayer_rbsp() 10 RSV_VCL_N10 Reserved non-IRAP sub-layer non- VCL 12 RSV_VCL_N12reference VCL NAL unit types 14 RSV_VCL_N14 11 RSV_VCL_R11 Reservednon-IRAP sub-layer VCL 13 RSV_VCL_R13 reference VCL NAL unit types 15RSV_VCL_R15 16 BLA_W_LP Coded slice segment of a broken VCL 17BLA_W_RADL link access (BLA) picture 18 BLA_N_LPslice_segment_layer_rbsp( ) 19 IDR_W_RADL Coded slice segment of an VCL20 IDR_N_LP instantaneous decoding refresh (IDR) pictureslice_segment_layer_rbsp( ) 21 CRA_NUT Coded slice segment of a cleanVCL random access (CRA) picture slice_segment_layer_rbsp( ) 22RSV_IRAP_VCL22 Reserved IRAP VCL NAL unit VCL 23 RSV_IRAP_VCL23 types 24. . . 31 RSV_VCL24 . . . Reserved non-IRAP VCL NAL unit VCL RSV_VCL31types 32 VPS_NUT Video parameter set non-video video_parameter_set_rbsp() coding layer (non-VCL) 33 SPS_NUT Sequence parameter set non-VCLseq_parameter_set_rbsp( ) 34 PPS_NUT Picture parameter set non-VCLpic_parameter_set_rbsp( ) 35 AUD_NUT Access unit delimiter non-VCLaccess_unit_delimiter_rbsp( ) 36 EOS_NUT End of sequence non-VCLend_of_seq_rbsp( ) 37 EOB_NUT End of bitstream non-VCLend_of_bitstream_rbsp( ) 38 FD_NUT Filler data non-VCL filler_data_rbsp() 39 PREFIX_SEI_NUT Supplemental enhancement non-VCL 40 SUFFIX_SEI_NUTinformation sei_rbsp( ) 41 . . . 47 RSV_NVCL41 . . . Reserved non-VCLRSV_NVCL47 48 . . . 63 UNSPEC48 . . . Unspecified non-VCL UNSPEC63

Referring to Table (2), the NAL unit header syntax may include two bytesof data, namely, 16 bits. The first bit is a “forbidden_zero_bit” whichis always set to zero at the start of a NAL unit. The next six bits is a“nal_unit_type” which specifies the type of raw byte sequence payloads(“RBSP”) data structure contained in the NAL unit as shown in Table (1).The next 6 bits is a “nuh_layer_id” which specify the indentifier of thelayer. In some cases these six bits may be specified as“nuh_reserved_zero_6 bits” instead. The nuh_reserved_zero _6 bits may beequal to 0 in the base specification of the standard. In a scalablevideo coding and/or syntax extensions nuh_layer_id may specify that thisparticular NAL unit belongs to the layer identified by the value ofthese 6 bits. The next syntax element is “nuh_temporal_id_plus1”. Thenuh_temporal_id_plus1 minus 1 may specify a temporal identifier for theNAL unit. The variable temporal identifier TemporalId may be specifiedas TemporalId=nuh_temporal_id_plus1−1. The temporal identifierTemporalId is used to identify a temporal sub-layer. The variableHighestTid identifies the highest temporal sub-layer to be decoded.

TABLE 2 Descriptor nal_unit_header( ) { forbidden_zero_bit f(1)nal_unit_type u(6) nuh_layer_id u(6) nuh_temporal_id_plus1 u(3) }

Referring to FIG. 8A, as previously described the NAL unit header syntaxmay include two bytes of data, namely, 16 bits. The first bit is a“forbidden_zero_bit” which is always set to zero at the start of a NALunit. The next six bits is a “nal_unit_type” which specifies the type ofraw byte sequence payloads (“RBSP”) data structure contained in the NALunit. The next 6 bits is a “nuh_reserved_zero_6 bits”. Thenuh_reserved_zero_6 bits may be equal to 0 in the base specification ofthe standard. Other values of nuh_reserved_zero_6 bits may be specifiedas desired. Decoders may ignore (i.e., remove from the bitstream anddiscard) all NAL units with values of nuh_reserved_zero_6 bits not equalto 0 when handling a stream based on the base specification of thestandard. In a scalable or other extension nuh_reserved_zero_6 bits mayspecify other values, to signal scalable video coding and/or syntaxextensions. In some cases syntax element nuh_reserved_zero_6 bits may becalled reserved_zero_6 bits. In some cases the syntax elementnuh_reserved_zero_6 bits may be called as layer_id_plus1 or layer _id,as illustrated in FIG. 8B and FIG. 8C. In this case the element layer_idwill be layer_id_plus1 minus 1. In this case it may be used to signalinformation related to layer of scalable coded video. The next syntaxelement is “nuh_temporal_id_plus1”. nuh_temporal_id_plus1 minus 1 mayspecify a temporal identifier for the NAL unit. The variable temporalidentifier TemporalId may be specified asTemporalId=nuh_temporal_id_plus1−1.

Referring to FIG. 9, a general NAL unit syntax structure is illustrated.The NAL unit header two byte syntax of FIG. 8 is included in thereference to nal_unit_header( ) of FIG. 9. The remainder of the NAL unitsyntax primarily relates to the RBSP.

One existing technique for using the “nuh_reserved_zero_6 bits” is tosignal scalable video coding information by partitioning the 6 bits ofthe nuh_reserved_zero_6 bits into distinct bit fields, namely, one ormore of a dependency identifier (ID), a quality ID, a view ID, and adepth flag, each of which refers to the identification of a differentlayer of the scalable coded video. Accordingly, the 6 bits indicate whatlayer of the scalable encoding technique this particular NAL unitbelongs to. Then in a data payload, such as a video parameter set(“VPS”) extension syntax (“scalability_type”) as illustrated in FIG. 10,the information about the layer is defined. The VPS extension syntax ofFIG. 10 includes 4 bits for scalability type (syntax elementscalability_type) which specifies the scalability types in use in thecoded video sequence and the dimensions signaled through layer_id_plus1(or layer_id) in the NAL unit header. When the scalability type is equalto 0, the coded video sequence conforms to the base specification, thuslayer_id_plus1 of all NAL units is equal to 0 and there are no NAL unitsbelonging to an enhancement layer or view. Higher values of thescalability type are interpreted as illustrated in FIG. 11.

The layer_id_dim_len[i] specifies the length, in bits, of the i-thscalability dimension ID. The sum of the values layer_id_dim_len[i] forall i values in the range of 0 to 7 is less than or equal to 6. Thevps_extension_byte_alignment_reserved_zero_bit is zero. Thevps_layer_id[i] specifies the value of layer_id of the i-th layer towhich the following layer dependency information applies. Thenum_direct_ref_layers[i] specifies the number of layers the i-th layerdirectly depends on. The ref_layer[i][j] identifies the j-th layer thei-th layer directly depends on.

In this manner, the existing technique signals the scalabilityidentifiers in the NAL unit and in the video parameter set to allocatethe bits among the scalability types listed in FIG. 11. Then for eachscalability type, FIG. 11 defines how many dimensions are supported. Forexample, scalability type 1 has 2 dimensions (i.e., spatial andquality). For each of the dimensions, the layer_id_dim_len[i] definesthe number of bits allocated to each of these two dimensions, where thetotal sum of all the values of layer_id_dim_len[i] is less than or equalto 6, which is the number of bits in the nuh_reserved_zero_6 bits of theNAL unit header. Thus, in combination the technique identifies whichtypes of scalability is in use and how the 6 bits of the NAL unit headerare allocated among the scalability.

As previously described, scalable video coding is a technique ofencoding a video bitstream that also contains one or more subsetbitstreams. A subset video bitstream may be derived by dropping packetsfrom the larger video to reduce the bandwidth required for the subsetbitstream. The subset bitstream may represent a lower spatial resolution(smaller screen), lower temporal resolution (lower frame rate), or lowerquality video signal. For example, a video bitstream may include 5subset bitstreams, where each of the subset bitstreams adds additionalcontent to a base bitstream. Hannuksela, et al., “Test Model forScalable Extensions of High Efficiency Video Coding (HEVC)” JCTVC-L0453,Shanghai, October 2012, is hereby incorporated by reference herein inits entirety. Chen, et al., “SHVC Draft Text 1,” JCTVC-L1008, Geneva,March, 2013, is hereby incorporated by reference herein in its entirety.J. Chen, J. Boyce, Y. Ye, M Hannuksela, SHVC Draft 3, JCTVC-N1008,Vienna, August 2013; and Y. Chen, Y.-K. Wang, A. K. Ramasubromanian,MV-HEVC/SHVC HLS: Cross-layer POC Alignment, JCTVC-N0244, Vienna, July2013; each of which is incorporated by reference herein in its entirety.

As previously described, multi-view video coding is a technique ofencoding a video bitstream that also contains one or more otherbitstreams representative of alternative views. For example, themultiple views may be a pair of views for stereoscopic video. Forexample, the multiple views may represent multiple views of the samescene from different viewpoints. The multiple views generally contain alarge amount of inter-view statistical dependencies, since the imagesare of the same scene from different viewpoints. Therefore, combinedtemporal and inter-view prediction may achieve efficient multi-viewencoding. For example, a frame may be efficiently predicted not onlyfrom temporally related frames, but also from the frames of neighboringviewpoints. Hannuksela, et al., “Common specification text for scalableand multi-view extensions,” JCTVC-L0452, Geneva, January 2013, is herebyincorporated by reference herein in its entirety. Tech, et. al. “MV-HEVCDraft Text 3 (ISO/IEC 23008-2:201x/PDAM2),” JCT3V-C1004_d3, Geneva,January 2013, is hereby incorporated by reference herein in itsentirety. G. Tech, K. Wegner, Y. Chen, M. Hannuksela, J. Boyce, “MV-HEVCDraft Text 5 (ISO/IEC 203008-2:201x/PDAM2), JCTVC-E1004, Vienna, August2013, is hereby incorporated by reference herein in its entirety.

Chen, et al., “SHVC Draft Text 1,” JCTVC-L1008, Geneva, January 2013;Hannuksela, et al. “Test Model for Scalable Extensions of HighEfficiency Video Coding (HEVC),” JCTVC-L0453-spec-text, Shanghai,October 2012; and Hannuksela, “Draft Text for Multiview Extension ofHigh Efficiency Video Coding (HEVC),” JCTVC-L0452-spec-text-r1,Shanghai, October 2012; each of which is incorporated by referenceherein in its entirety.

Referring to FIG. 12, when coding scalable high efficiency coding (SHVC)the base layer may include one or more SPS and may also include one ormore picture parameter sets (PPS). Also, each enhancement layer mayinclude one or more SPS and may also include one or more PPS. In FIG. 12SPS+ indicates one or more SPS and PPS+ indicates one or more PPS beingsignaled for a particular base or enhancement layer. In this manner, fora video bitstream having both a base layer and one or more enhancementlayers, the collective number of SPS and PPS data sets becomessignificant together with the required bandwidth to transmit such data,which tends to be limited in many applications. With such bandwidthlimitations, it is desirable to limit the data that needs to betransmitted, and locate the data in the bitstream in an effectivemanner. Each layer may have one SPS and/or PPS that is activate at anyparticular time, and may select a different active SPS and/or PPS, asdesired.

An input picture may comprise a plurality of coded tree blocks (e.g.,generally referred to herein as blocks) may be partitioned into one orseveral slices. The values of the samples in the area of the picturethat a slice represents may be properly decoded without the use of datafrom other slices provided that the reference pictures used at theencoder and the decoder are the same and that de-blocking filtering doesnot use information across slice boundaries. Therefore, entropy decodingand block reconstruction for a slice does not depend on other slices. Inparticular, the entropy coding state may be reset at the start of eachslice. The data in other slices may be marked as unavailable whendefining neighborhood availability for both entropy decoding andreconstruction. The slices may be entropy decoded and reconstructed inparallel. No intra prediction and motion-vector prediction is preferablyallowed across the boundary of a slice. In contrast, de-blockingfiltering may use information across slice boundaries.

FIG. 13 illustrates an exemplary video picture 2090 comprising elevenblocks in the horizontal direction and nine blocks in the verticaldirection (nine exemplary blocks labeled 2091-2099). FIG. 13 illustratesthree exemplary slices: a first slice denoted “SLICE #0” 2080, a secondslice denoted “SLICE #1” 2081 and a third slice denoted “SLICE #2” 2082.The decoder may decode and reconstruct the three slices 2080, 2081, 2082in parallel. Each of the slices may be transmitted in scan line order ina sequential manner. At the beginning of the decoding/reconstructionprocess for each slice, context models are initialized or reset andblocks in other slices are marked as unavailable for both entropydecoding and block reconstruction. The context model generallyrepresents the state of the entropy encoder and/or decoder. Thus, for ablock, for example, the block labeled 2093, in “SLICE #1,” blocks (forexample, blocks labeled 2091 and 2092) in “SLICE #0” may not be used forcontext model selection or reconstruction. Whereas, for a block, forexample, the block labeled 2095, in “SLICE #1,” other blocks (forexample, blocks labeled 2093 and 2094) in “SLICE #1” may be used forcontext model selection or reconstruction. Therefore, entropy decodingand block reconstruction proceeds serially within a slice. Unless slicesare defined using a flexible block ordering (FMO), blocks within a sliceare processed in the order of a raster scan.

Flexible block ordering defines a slice group to modify how a picture ispartitioned into slices. The blocks in a slice group are defined by ablock-to-slice-group map, which is signaled by the content of thepicture parameter set and additional information in the slice headers.The block-to-slice-group map consists of a slice-group identificationnumber for each block in the picture. The slice-group identificationnumber specifies to which slice group the associated block belongs. Eachslice group may be partitioned into one or more slices, wherein a sliceis a sequence of blocks within the same slice group that is processed inthe order of a raster scan within the set of blocks of a particularslice group. Entropy decoding and block reconstruction proceeds seriallywithin a slice group.

FIG. 14 depicts an exemplary block allocation into three slice groups: afirst slice group denoted “SLICE GROUP #0” 2083, a second slice groupdenoted “SLICE GROUP #1” 2084 and a third slice group denoted “SLICEGROUP #2” 2085. These slice groups 2083, 2084, 2085 may be associatedwith two foreground regions and a background region, respectively, inthe picture 2090.

The arrangement of slices, as illustrated in FIG. 14, may be limited todefining each slice between a pair of blocks in the image scan order,also know as raster scan or a raster can order. This arrangement of scanorder slices is computationally efficient but does not tend to lenditself to the highly efficient parallel encoding and decoding. Moreover,this scan order definition of slices also does not tend to group smallerlocalized regions of the image together that are likely to have commoncharacteristics highly suitable for coding efficiency. The arrangementof slice groups 2083, 2084, 2085, as illustrated in FIG. 14, is highlyflexible in its arrangement but does not tend to lend itself to highefficient parallel encoding or decoding. Moreover, this highly flexibledefinition of slices is computationally complex to implement in adecoder.

Referring to FIG. 15, a tile technique divides an image into a set ofrectangular (inclusive of square) regions. The blocks (alternativelyreferred to as largest coding units or coded treeblocks in some systems)within each of the tiles are encoded and decoded in a raster scan order.The arrangement of tiles are likewise encoded and decoded in a rasterscan order. Accordingly, there may be any suitable number of columnboundaries (e.g., 0 or more) and there may be any suitable number of rowboundaries (e.g., 0 or more). Thus, the frame may define one or moreslices, such as the one slice illustrated in FIG. 15. In some examples,blocks located in different tiles are not available forintra-prediction, motion compensation, entropy coding context selectionor other processes that rely on neighboring block information.

Referring to FIG. 16, the tile technique is shown dividing an image intoa set of three rectangular columns. The blocks (alternatively referredto as largest coding units or coded treeblocks in some systems) withineach of the tiles are encoded and decoded in a raster scan order. Thetiles are likewise encoded and decoded in a raster scan order. One ormore slices may be defined in the scan order of the tiles. Each of theslices are independently decodable. For example, slice 1 may be definedas including blocks 1-9, slice 2 may be defined as including blocks10-28, and slice 3 may be defined as including blocks 29-126 which spansthree tiles. The use of tiles facilitates coding efficiency byprocessing data in more localized regions of a frame.

Referring to FIG. 17, the base layer and the enhancement layers may eachinclude tiles which each collectively form a picture or a portionthereof. The coded pictures from the base layer and one or moreenhancement layers may collectively form an access unit. The access unitmay be defined as a set of NAL units that are associated with each otheraccording to a specified classification rule, are consecutive indecoding order, and/or contain the VCL NAL units of all coded picturesassociated with the same output time (picture order count or otherwise)and their associated non-VCL NAL units. The VCL NAL is the video codinglayer of the network abstraction layer. Similarly, the coded picture maybe defined as a coded representation of a picture comprising VCL NALunits with a particular value of nuh_layer_id within an access unit andcontaining all coding tree units of the picture. Additional descriptionsare described in B. Bros, W-J. Han, J-R, Ohm, G. J. Sullivan, and T.Wiegand, “High efficiency video coding (HEVC) text specification draft10,” JCTVC-L1003, Geneva, January 2013; J. Chen, J. Boyce, Y. Ye, M. M.Hannuksela, “SHVC Draft Text 2,” JCTVC-M1008, Incheon, May 2013; G.Tech, K. Wegner, Y. Chen, M. Hannuksela, J. Boyce, “MV-HEVC Draft Text 4(ISO/IEC 23008-2:201x/PDAM2),” JCTVC-D1004, Incheon, May 2013; each ofwhich is incorporated by reference herein in its entirety.

Referring to FIGS. 18A-18D, each slice may include a slice segmentheader. In some cases a slice segment header may be called slice header.Within the slice segment header there includes syntax elements that areused for inter-layer prediction. This inter-layer prediction defineswhat other layers the slice may depend upon. In other words thisinter-layer prediction defines what other layers the slice may use asits reference layers. The reference layers may be used for sampleprediction and or for motion filed prediction. Referring to FIG. 19 byway of example, enhancement layer 3 may depend upon enhancement layer 2,and base layer layer 0. This dependency relationship may be expressed inthe form of a list, such as, [2, 0].

The NumDirectRefLayers for a layer may be derived based upon adirect_dependency_flag[i][j] that when equal to 0 specifies that thelayer with index j is not a direct reference layer for the layer withindex i. The direct_dependency_flag[i][j] equal to 1 specifies that thelayer with index j may be a direct reference layer for the layer withindex i. When direct_dependency_flag[i][j] is not present for i and j inthe range of 0 to vps_max_layers_minus1, it is inferred to be equal to0.

The variables NumDirectRefLayers[i], RefLayerId[i][j]SamplePredEnabledFlag[i][j], MotionPredEnabledFlag[i][j] andDirectRefLayerIdx[i][j] may be derived as follows:

for( i = 0; i <= vps_max_layers_minus1; i++ ) { iNuhLId =layer_id_in_nuh[ i ] NumDirectRefLayers[ iNuhLId ] = 0 for( j = 0; j <i; j++ ) if( direct_dependency_flag[ i ][ j ] ) { RefLayerId[ iNuhLId ][NumDirectRefLayers[ iNuhLId ]++ ] = layer_id_in_nuh[ j ]SamplePredEnabledFlag[ iNuhLId ][ j ] = ( ( direct_dependency_type[ i ][j ] + 1 ) & 1 ) MotionPredEnabledFlag[ iNuhLid ][ j ] = ( ( (direct_dependency_type[ i ][ j ] + 1 ) & 2 ) >> 1 ) DirectRefLayerIdx[iNuhLid ][ layer_id_in_nuh[ j ] ] = NumDirectRefLayers[ iNuhLid ] − 1 }}

The direct_dep_type_len_minus2 plus 2 specifies the number of bits ofthe direct_dependency_type[i][j] syntax element. In bitstreamsconforming to this version of this Specification the value ofdirect_dep_type_len_minus2 may be equal 0. Although the value ofdirect_dep_type_len_minus2 may be equal to 0 in this version of thisSpecification, decoders may allow other values ofdirect_dep_type_len_minus2 in the range of 0 to 30, inclusive, to appearin the syntax.

The direct_dependency_type[i][j] indicates the type of dependencybetween the layer with nuh_layer_id equal layer_id_in_nuh[i] and thelayer with nuh_layer_id equal to layer_id_in_nuh[j].direct_dependency_type[i][j] equal to 0 indicates that the layer withnuh_layer_id equal to layer_id_in_nuh[j] is used for inter-layer sampleprediction but not for inter-layer motion prediction of the layer withnuh _id equal layer_id_in_nuh[i]. direct_dependency_type[i][j] equal to1 indicates that the layer with nuh_layer_id equal to layer_id_in_nuh[j]is used for inter-layer motion prediction but not for inter-layer sampleprediction of the layer with nuh_layer_id equal layer_id_in_nuh[i].direct_dependency_type[i][j] equal to 2 indicates that the layer withnuh_layer_id equal to layer_id_in_nuh[j] is used for both inter-layersample motion prediction and inter-layer motion prediction of the layerwith nuh_layer_id equal layer_id_in_nuh[i]. Although the value ofdirect_dependency_type[i][j] may be in the range of 0 to 2, inclusive,in this version of this Specification, decoders may allow values ofdirect_dependency_type[i][j] in the range of 3 to 232−2, inclusive, toappear in the syntax.

The direct_dependency_flag[i][j], direct_dep_type_len_minus2,direct_dependency_type[i][j] are included in the vps_extension syntaxillustrated in FIG. 20A and FIG. 20B, which is included by reference inthe VPS syntax which provides syntax for the coded video sequence.

It is typically desirable to reduce the number of referenced layers thatneed to he signaled within the bitstream, and other syntax elementswithin the slice segment header may be used to effectuate such areduction. The other syntax elements may includeinter_layer_pred_enabled_flag, num_inter_layer_ref_pics_minus1, and/orinterlayer_pred_layer_idc[i]. These syntax elements may be signaled inslice segment header.

The inter_layer_pred_enabled_flag equal to 1 specifies that inter-layerprediction may be used in decoding of the current picture. Theinter_layer_pred_enabled_flag equal to 0 specifies that inter-layerprediction is not used in decoding of the current picture. When notpresent, the value of inter_layer_pred_enabled_flag is inferred to beequal to 0.

The num_inter_layer_ref_pics_minus1 plus 1 specifies the number ofpictures that may be used in decoding of the current picture forinter-layer prediction. The length of thenum_inter_layer_ref_pics_minus1 syntax element is Ceil(Log2(NumDirectRefLayers[nuh_layer_id])) bits. The value ofnum_inter_layer_ref_pics_minus1 may be in the range of 0 toNumDirectRefLayers[nuh_layer_id]−1, inclusive.

The variable NumActiveRefLayerPics is derived as follows:

if( nuh_layer_id = = 0 | | NumDirectRefLayers[ nuh_layer_id ] = = 0 || !inter_layer_pred_enabled_flag ) NumActiveRefLayerPics = 0 else if(max_one_active_ref_layer_flag | | NumDirectRefLayers[ nuh_layer_id ] = =1 ) NumActiveRefLayerPics = 1 else NumActiveRefLayerPics =num_inter_layer_ref_pics_minus1 + 1

All slices of a coded picture may have the same value ofNumActiveRefLayerPics.

The inter_layer_pred_layer_idc[i] specifies the variable,RefPicLayerId[i], representing the nuh_layer_id of the i-th picture thatmay be used by the current picture for inter-layer prediction. Thelength of the syntax element inter_layer_pred_layer_idc[i] is Ceil(Log2(NumDirectRefLayers[nuh_layer_id])) bits. The value ofinter_layer_pred_layer_idc[i] may be in the range of 0 toNumDirectRefLayers[nuh_layer_id]−1, inclusive. When not present, thevalue of inter_layer_pred_layer_idc[i] is inferred to be equal to 0.

By way of example, the system may signal various syntax elementsespecially the direct_dependency_flag[i][j] in VPS which results in theinter-layer reference picture set for layer 3 to be [2, 0]. Then thesystem may refine further the inter-layer reference picture set with theuse of the additional syntax elements for example syntax elements inslice segment header as [2], may refine further the inter-layerreference picture set with the use of the additional syntax elements as[0], or may refine further the inter-layer reference picture set withthe use of the additional syntax elements as [ ] which is the null set.However, depending on the design of the encoder, the reference pictureset of [2, 0] may be signaled as [2, 0].

FIG. 21 shows an exemplary representation format syntax. This maycorrespond to the rep_format( ) structure in FIG. 20B an exemplary vpsextension syntax.

FIG. 22 shows an exemplary VPS Video Usability Information (VUI) syntax.This may correspond to the vps_vui( ) structure in FIG. 20B andexemplary vps extension syntax.

FIG. 23 shows another exemplary VPS Video Usability Information (VUI)syntax with some differences in syntax compared to FIG. 22. This maycorrespond to the vps_vui( ) structure in FIG. 20B and exemplary vpsextension syntax.

In FIG. 20B the vps_vui_present_flag equal to 1 specifies that thevps_vui( ) syntax structure is present in the VPS. vps_vui_present_flagequal to 0 specifies that the vps_vui( ) syntax structure is not presentin the VPS. vps_vui_alignment_bit_equal_to_one may be equal to 1.

VPS VUI includes syntax elements which indicate inter-layer predictionrestrictions. These include syntax elementsilp_restricted_ref_layers_flag, min_spatial_segment_offset_plus1[i][j],ctu_based_offset_enabled_flag[i][j], andmin_horizontal_ctu_offset_plus1[i][j]. Essentially depending on spatialsegmentation tools used a delay in units of slices, tiles, wavefrontcoded tree block (CTB) rows with respect to the collocated spatialsegment in the reference layer may be signaled. Also based on flag adelay in units of CTBs may be signaled. These inter-layer decoding delaysignaling can help parallel decoding of layers, where for a dependentlayer instead of waiting for each reference layer to be decodedcompletely in its entirety before starting its own decoding, thedecoding could be started after the indicated delay for each referencelayer.

In FIG. 22 syntax elements NumDirectRefLayers[layer_in_in_nuh[i]] numberof {min_spatial_segment_offset_plus1[i][j],ctu_based_offset_enabled_flag[i][j],min_horizontal_ctu_offset_plus1[i][j]} syntax elements are signaled foreach direct reference layer for each layer for such delay indication. Asignaling optimization for vps vui is shown in FIG. 23 where acommon_ilp_offset_params_flag[i] syntax element is signaled. When thecommon_ilp_offset_params[i] is equal to 1 then instead of signalingsyntax elements {min_spatial_segment_offset_plus1[i][j],ctu_based_offset_enabled_flag[i][j],min_horizontal_ctu_offset_plus1[i][j]} individuallyNumDirectRefLayers[layer_in_in_nuh[i]] number of times, a common valuefor those syntax elements is signaled only once and inferred for otherlayers. In a typical coding scenario using a regular coding structurethe inter-layer prediction restriction i.e. inter-layer decoding delayindication values indicated for direct reference layers of a dependentlayers will be similar and could be more efficiently signaled using thesyntax in FIG. 23 compared to syntax in FIG. 22.

As an example currently if a layer 5 is dependent on layer 0, 1, 2, 3,and 4 and a regular coding structure is used with tiles such that thesame values of say {7, 7, 7, 7, 7} are signaled 5 times (once for eachof reference layers 0, 1, 2, 3 and 4 of the layer 5) formin_spatial_segment_offset_plus1[i][j] syntax element when usingsignaling shown in FIG. 22. Instead when using signaling shown in FIG.23 the flag common_ilp_offset_params_present_flag[i] can be signaled as1 and value 7 can be signaled for min_spatial_segment_offset_plus1[i][j]only once (instead of 5 times) and can be applied to all the 5 referencelayers 0, 1, 2, 3 and 4 of the layer 5.

The ilp_restricted_ref_layers_flag equal to 1 indicates that additionalrestrictions on inter-layer prediction as specified below apply for eachdirect reference layer of each layer specified by the VPS.ilp_restricted_ref_layers_flag equal to 0 indicates that additionalrestrictions on inter-layer prediction may or may not apply.

The variables refCtbLog 2SizeY[i][j], refPicWidthInCtbsY[i][j], andrefPicHeightInCtbsY[i][j] are set equal to CtbLog 2SizeY,PicWidthInCtbsY, and PicHeightInCtbsY, respectively, of the j-th directreference layer of the i-th layer.

The common_ilp_offset_params_present_flag[i] equal to 0 specifies thatmin_spatial_segment_offset_plus1[i][j],ctu_based_offset_enabled_flag[i][j],min_horizontal_ctu_offset_plus1[i][j] are present forNumDirectRefLayers[layer_id_in_nuh[i]] layers for the i-th layer.common_ilp_offset_params_present_flag[i] equal to 1 specifies that thevalues of min_spatial_segment_offset_plus1[i][0],ctu_based_offset_enabled_flag[i][0], and when presentmin_horizontal_ctu_offset_plus1[i][0] apply to allNumDirectRefLayers[layer_id_in_nuh[i]] layers for the i-th layer.

The min_spatial_segment_offset_plus1[i][j] indicates the spatial region,in each picture of the j-th direct reference layer of the i-th layer,that is not used for inter-layer prediction for decoding of any pictureof the i-th layer, by itself or together withmin_horizontal_ctu_offset_plus1[i][j], as specified below. The value ofmin_spatial_segment_offset_plus1[i][j] may be in the range of 0 torefPicWidthInCtbsY[i][j]*refPicHeightInCtbsY[i][j], inclusive. When notpresent, if common_ilp_offset_params_present_flag[i] is equal to 1 thevalue of min_spatial_segment_offset_plus1[i][j] if is inferred to beequal to min_spatial_segment_offset_plus1[i][j] otherwise the value ofmin_spatial_segment_offset_plus1[i][j] is inferred to be equal to 0.

The ctu_based_offset_enabled_flag[i][j] equal to 1 specifies that thespatial region, in units of CTUs, in each picture of the j-th directreference layer of the i-th layer, that is not used for inter-layerprediction for decoding of any picture of the i-th layer is indicated bymin_spatial_segment_offset_plus1[i][j] andmin_horizontal_ctu_offset_plus1[i][j] together.ctu_based_offset_enabled_flag[i][j] equal to 0 specifies that thespatial region, in units of slice segments, tiles, or codec tree unit(CTU) rows, in each picture of the j-th direct reference layer of thei-th layer, that is not used for inter-layer prediction for decoding ofany picture of the i-th layer is indicated bymin_spatial_segment_offset_plus1[i] only. When not present, ifcommon_ilp_offset_params_present_flag[i] is equal to 1 the value ofctu_based_offset_enabled_flag[i][j] if is inferred to be equal toctu_based_offset_enabled_flag[i][j] otherwise the value ofctu_based_offset_enabled_flag[i] is inferred to be equal to 0.

The min_horizontal_ctu_offset_plus1[i][j], whenctu_based_offset_enabled_flag[i][j] is equal to 1, indicates the spatialregion, in each picture of the j-th direct reference layer of the i-thlayer, that is not used for inter-layer prediction for decoding of anypicture of the i-th layer, together withmin_spatial_segment_offset_plus1[i][j], as specified below. The value ofmin_horizontal_ctu_offset_plus1[i][j] may be in the range of 0 torefPicWidthInCtbsY[i][j], inclusive.

When ctu_based_offset_enabled_flag[i][j] is equal to 1, the variableminHorizontalCtbOffset[i][j] is derived as follows:minHorizontalCtbOffset[i][j]=(min_horizontal_ctu_offset_plus1[i][j]>0)!(min_horizontal_ctu_offset_plus1[i][j]−1):(refPicWidthInCtbsY[i][j]1)

The variables curPicWidthInSamplesL[i], curPicHeightInSamplesL[i],curCtbLog 2SizeY[i], curPicWidthInCtbsY[i], and curPicHeightInCtbsY[i]arc set equal to PicWidthInSamplesL, PicHeightInSamplesL, CtbLog 2SizeY,PicWidthInCtbsY, and PicHeightInCtbsY, respectively, of the i-th layer.

The variables refPicWidthInSamplesL[i][j], refPicHeightInSamplesL[i][j],refCtbLog 2SizeY[i][j], refPicWidthInCtbsY[i][j], andrefPicHeightInCtbsY[i][j] are set equal to PicWidthInSamplesL,PicHeightInSamplesL, CtbLog 2SizeY, PicWidthInCtbsY, andPicHeightInCtbsY, respectively, of the j-th direct reference layer ofthe i-th layer.

The variables curScaledRefLayerLeftOffset[i][j],curScaledRefLayerTopOffset[i][j], curScaledRefLayerRightOffset[i][j] andcurScaledRefLayerBottomOffset[i][j] are set equal toscaled_ref_layer_left_offset[j]<<1, scaled_ref_layer_top_offset[j]<<1,scaled_ref_layer_right_offset[j]<<1,scaled_ref_layer_bottom_offset[j]<<1, respectively, of the j-th directreference layer of the i-th layer.

The variable colCtbAddr[i][j] that denotes the raster scan address ofthe collocated CTU, in a picture in the j-th direct reference layer ofthe i-th layer, of the CTU with raster scan address equal to ctbAddr ina picture of the i-th layer is derived as follows:

-   -   The variables (xP, yP) specifying the location of the top-left        luma sample of the CTU with raster scan address equal to ctbAddr        relative to top-left luma luma sample in a picture of the i-th        layer are derived as follows:

xP=(ctbAddr % curPicWidthInCtbsY[i])<<curCtbLog 2SizeY

yP=(ctbAddr/curPicWidthInCtbsY[i])<<curCtbLog 2SizeY

-   -   The variables scaleFactorX[i][j] and scaleFactorY[i][j] are        derived as follows:

curScaledRefLayerPicWidthInSamples_(L)[i][j]=curPicWidthInSamples_(L)[i]−curScaledRefLayerLeftOffset[i][j]−curScaledRefLayerRightOffset[i][j]

curScaledRefLayerPicHeightInSamples_(L)[i][j]=curPicHeightInSamples_(L)[i]−curScaledRefLayerTopOffset[i][j]−curScaledRefLayerBottomOffset[i][j]

scaleFactorX[i][j]=((refPicWidthInSamples_(L)[i][j]<<16)+(curScaledRefLayerPicWidthInSamples_(L)[i][j]>>1)/curScaledRefLayerPicWidthInSamples_(L)[i][j]

scaleFactorY[i][j]=((refPicHeightInSamples_(L)[i][j]<<16)+(curScaledRefLayerPicHeightInSamples_(L)>>1))/curScaledRefLayerPicHeightInSamples_(L)[i][j]

-   -   The variables (xCol[i][j], yCol xCol[i][j]) specifying the        collocated luma sample location In a picture in the j-th direct        reference layer of the luma sample location (xP, yP) in the i-th        layer are derived as follows:

xCol[i][j]=Clip3(0, (refPicWidthInSamples_(L)[i][j]−1),

((xP−curScaledRefLayerLeftOffset[i][j])*scaleFactorX[i][j]+(1<<15))>>16))

yCol[i][j]=Clip3(0, (refPicHeightInSamples_(L)[i][j]−1),

((yP−curScaledRefLayerTopOffset[i][j )*scaleFactorY[i][j]+(1<<15))>>16))

-   -   The variable colCtbAddr[i][j] is derived as follows:

xColCtb[i][j]=xCol[i][j]>>refCtbLog 2SizeY[i][j]

yColCtb[i][j]=yCol[i][j]>>refCtbLog 2SizeY[i][j]

colCtbAddr[i][j]=xColCtb[i][j]+(yColCtb[i][j]*refPicWidthInCtbsY[i][j])

When min_spatial_segment_offset_plus1[i][j] is greater than 0, it is arequirement of bitstream conformance that the following may apply:

-   -   If ctu_based_offset_enabled_flag[i][j] is equal to 0, exactly        one of the following applies:        -   In each PPS referred to by a picture in the j-th direct            reference layer of the i-th layer, tiles_enabled_flag is            equal to 0 and entropy_coding_sync_enabled_flag is equal to            0, and the following applies:            -   Let slice segment A be any slice segment of a picture of                the i-th layer and ctbAddr be the raster scan address of                the last CTU in slice segment A. Let slice segment B be                the slice segment that belongs to the same access unit                as slice segment A, belongs to the j-th direct reference                layer of the i-th layer, and contains the CTU with                raster scan address colCtbAddr[i][j]. Let slice segment                C be the slice segment that is in the same picture as                slice segment B end follows slice segment B in decoding                order, and between slice segment B and that slice                segment there are min_spatial_segment_offset_plus1[i]−1                slice segments in decoding order. When slice segment C                is present, the syntax elements of slice segment A are                constrained such that no sample or syntax elements                values in slice segment C or any slice segment of the                same picture following C in decoding order are used for                inter-layer prediction in the decoding process of any                samples within slice segment A.    -   In each PPS referred to by a picture in the j-th direct        reference layer of the i-th layer, tiles_enabled_flag is equal        to 1 and entropy_coding_sync_enabled_flag is equal to 0, and the        following applies:        -   Let tile A be any tile in any picture picA of the i-th layer            and ctbAddr be the raster scan address of the last CTU in            tile A. Let tile B be the tile that is in the picture picB            belonging to the same access unit as picA and belonging to            the j-th direct reference layer of the i-th layer and that            contains the CTU with raster scan address colCtbAddr[i][j].            Let tile C be the tile that is also in picB and follows tile            B in decoding order, and between tile B and that tile there            are min_spatial_segment_offset_plus1[i]−1 tiles in decoding            order. When slice segment C is present, the syntax elements            of tile A are constrained such that no sample or syntax            elements values in tile C or any tile of the same picture            following C in decoding order are used for inter-layer            prediction in the decoding process of any samples within            tile A.        -   In each PPS referred to by a picture in the j-th direct            reference layer of the i-th layer, tiles_enabled_flag is            equal to 0 and entropy_coding_sync_enabled_flag is equal to            1, and the following applies:            -   Let CTU row A be any CTU row in any picture picA of the                i-th layer and ctbAddr be the raster scan address of the                last CTU in CTU row A. Let CTU row B be the CTU row that                is in the picture picB belonging to the same access unit                as picA and belonging to the j-th direct reference layer                of the i-th layer and that contains the CTU with raster                scan address colCtbAddr[i][j]. Let CTU row C be the CTU                row that is also in picB and follows CTU row B in                decoding order, and between CTU row B and that CTU row                there are min_spatial_segment_offset_plus1[i]−1 CTU rows                in decoding order. When CTU row C is present, the syntax                elements of CTU row A are constrained such that no                sample or syntax elements values in CTU row C or row of                the same picture following C are used for inter-layer                prediction in the decoding process of any samples within                CTU row A.    -   Otherwise (ctu_based_offset_enabled_flag[i][j] is equal to 1),        the following applies:    -   The variable refCtbAddr[i][j] is derived as follows:

xOffset[i][j]=((xColCtb[i][j]+minHorizontalCtbOffset[i][j])>(refPicWidthInCtbsY[i][j]−1))?

(refPcWidthInCtbsY[i][j]−1−xColCtb[i][j]):(minHorizontalCtbOffset[i][j])

yOffset[i][j]=(min_spatial_segment_offset_plus1[i][j]−1)*refPicWidthInCtbsY[i][j]

refCtbAddr[i][j]=colCtbAddr[i][j]+xOffset[i][j]+yOffset[i][j]

-   -   -   Let CTU A be any CTU in any picture picA of the i-th layer,            and ctbAddr be the raster scan address ctbAddr of CTU A. Let            CTU B be a CTU that is in the picture belonging to the same            access unit as picA and belonging to the j-th direct            reference layer of the i-th layer and that has raster scan            address greater than refCtbAddr[i][j]. When CTU B is            present, the syntax elements of CTU A are constrained such            that no sample or syntax elements values in CTU B are used            for inter-layer prediction in the decoding process of any            samples within CTU A.

Additional descriptions of HEVC, scalable high efficiency video coding(SHVC) and MV-HEVC video coding are described in B. Bros, W-J. Han, J-R.Ohm, G. J. Sullivan, and T. Wiegand, “High efficiency video coding(HEVC) text specification draft 10,” JCTVC-L1003, Geneva, January 2013;G. Tech, K. Wegner, Y. Chen, M. Hannuksela, J. Boyce, “MV-HEVC DraftText 7 (ISO/IEC 23008-2:201x/PDAM2),” JCTVC-G1004, San Jose, January2014; each of which is incorporated by reference herein in its entirety.J. Chen, J. Boyce, Y. Ye, M. M. Hannuksela, “High Efficiency VideoCoding (HEVC) Scalable Extension Draft 5”, JCTVC-P1008, San Jose,January 2014, is incorporated by reference herein in its entirety.

FIG. 24A illustrates an exemplary video parameter set (VPS) syntax. Inone example the VPS syntax shown in FIG. 24A may be carried inside aHEVC coded video bitstream. FIG. 24B illustrates an exemplary videoparameter set (VPS) syntax. In one example the VPS syntax shown in FIG.24B may be carried inside a SHVC and/or MV-HEVC coded video bitstream.VPS may include a VPS extension—vps_extension syntax FIG. 25 illustratesan exemplary video parameter set (VPS) extension syntax. VPS extensionmay include a vps video usability information syntax structure. FIG. 26illustrates an exemplary vps video usability information (VPS VUI)syntax

FIG. 27 illustrates an exemplary sequence parameter set (SPS) extensionsyntax. SPS may include a sps video usability information syntaxstructure. FIG. 28 illustrates an exemplary sps video usabilityinformation (SPS VUI)

FIG. 29 illustrates an exemplary profile_tier_level syntax structure. Inone example the profile_tier_level syntax structure as shown in FIG. 28may be carried in VPS and SPS of a video coded according to HEVCInternational standard specification.

FIG. 30 illustrates an exemplary profile_tier_level syntax. In oneexample the profile_tier_level syntax structure as shown in FIG. 28 maybe carried in VPS and SPS of a video coded according to SHVC and/orMV-HEVC International standard specification. In particular theprofile_tier_level may be carried in the VPS as shown in FIG. 24 and

The profile_tier_level( ) syntax structure provides profile, tier andlevel information used for a layer set. When the profile_tier_level( )syntax structure is included in a vps_extension( ) syntax structure, theapplicable layer set to which the profile_tier_level( ) syntax structureapplies is specified by the corresponding IsIdx variable in thevps_extension( ) syntax structure. When the profile_tier_level( ) syntaxstructure is included in a VPS, but not in a vps extension( ) syntaxstructure, the applicable layer set to which the profile_tier_level( )syntax structure applies is the layer set specified by the index 0. Whenthe profile_tier_level( ) syntax structure is included in an SPS, thelayer set to which the profile_tier_level( ) syntax structure applies isthe layer set specified by the index 0.

It is desirable to have additional constraints on coded video. In oneexample the coded video may be carried in video subsystem of digitaltelevision standards. Particular constraints on coded video may becarried in video subsystem of Advanced Television Standards Committee(ATSC) 3.0 standard and other standards.

The additional constraints may be suitable for the carriage of HEVCvideo in ATSC. Additional constraints may be suitable for carriage ofSHVC video in ATSC.

Thus the constraints are preferably applicable if either HEVC and/orSHVC are selected as video codec for carriage of coded video in videosubsystem of ATSC 3.0 standard.

Constraints may include, for example, any of the following syntaxelements for both HEVC and SHVC coded video carried in ATSC 3.0 videosubsystem:

-   -   Constraints are defined on general_progressive_source_flag,        general_interlaced_source_flag and        general_frame_only_constraint_flag in profile_tier_level syntax        structure in Sequence Parameter Set (SPS) and Video Parameter        Set (VPS). These constraints make sure that only progressive        source scan pictures are in the coded video bitstream.    -   Constraints on vui_parameters_present_flag, field_seq_flag and        frame_field_info_present_flag in Sequence Parameter Set (SPS).        These constraints make sure that SPS VUI parameters are signaled        in the bitstream and that only progressive source scan pictures        are in the coded video bitstream.    -   Constraints on vui_parameters_present_flag,        vui_timing_info_present_flag vui_hrd_parameters_present_flag,        fixed_pic_fate_general_flag[i] and        fixed_pic_rate_within_cvs_flag[i] in SPS. These constraints make        sure that only fixed picture rate (fixed frame rate) is allowed        in the coded video bitstream.

The following constraints may be included for SHVC coded video carriedin ATSC 3.0 video subsystem

-   -   Constraints on vps_extension_flag. This makes sure        vps_extension( ) is present in the video bitstream.    -   Constraints on general_progressive_source_flag,        general_interlaced_source_flag and        general_frame_only_constraint_flag in profile_tier_level syntax        structure in vps_extension( ). These constraints make sure that        only progressive source scan pictures are in the coded video        bitstream.    -   Constraints on vps_vui_present_flag, pic_rate_present_vps_flag,        pic_rate_present_flag[i][j] and constant_pic_rate_idc[i][j].        These constraints make sure that VPS VUI parameters are signaled        in the bitstream and that only progressive source scan pictures        are in the coded video.    -   Constraints on vui_parameters_present_flag,        vui_timing_info_present_flag vui_hrd_parameters_present_flag,        fixed_pic_rate_general_flag[i] and        fixed_pic_rate_within_cvs_flag[i] in VPS and vps_extension( ).        These constraints make sure that only fixed picture rate (fixed        frame rate) is allowed in the coded video bitstream.

It is preferable that only progressive source scan type is supported forpictures in the coded video to be carried in the video subsystem with nosupport for interlaced source scan type. The preferable bitstreamconstraints correspond to this restriction which only allows progressivescan type pictures to be coded and do not allow interlaced source scantype pictures to be coded in the video bitstream carried in the videosubsystem.

It is also preferable that only fixed picture rate is supported and thatbase layer and enhancement layer have the same picture rate. Bothinteger and fractional picture rates may be supported. The term picturerate and frame rate may be used interchangeably. Carrying coded videowhich does not have fixed picture rate or fixed frame rate may notprovide any benefits but may hamper viewer experience as human visualsystem has to adjust between content with different picture rate ordifferent frame rate. The preferable bitstream constraints correspond tothis restriction, which only allows fixed picture rate. The preferablebitstream constraints may further impose a restriction which requiredthe base layer and enhancement layer to have the same fixed picture rateor fixed frame rate.

The following constraints are preferable for both HEVC and SHVC codedvideo carried in ATSC 3.0 video subsystem:

general_progressive_source_flag and general_interlaced_source_flag maybe interpreted as follows:

-   -   If general_progressive_source_flag is equal to 1 and general        interlaced_source_flag is equal to 0, the source scan type of        the pictures in the CVS should be interpreted as progressive        only.    -   Otherwise, if general_progressive_source_flag is equal to 0 and        general_interlaced_source_flag is equal to the source scan type        of the pictures in the CVS should be interpreted as interlaced        only.    -   Otherwise, if general_progressive_source_flag is equal to 0 and        general_interlaced_source_flag is equal to 0, the source scan        type of the pictures in the CVS should be interpreted as unknown        or unspecified.    -   Otherwise (general_progressive_source_flag is equal to 1 and        general_interlaced_source_flag is equal to 1), the source scan        type of each picture in the CVS is indicated at the picture        level using the syntax element source_scan_type in a picture        timing SEI message.

Decoders may ignore the values of general_progressive_source_flag andgeneral_interlaced_source_flag for purposes other than determining thevalue to be inferred for frame_field_info_present_flag whenvui_parameters_present_flag is equal to 0, as there are no otherdecoding process requirements associated with the values of these flags.Moreover, the actual source scan type of the pictures may be anysuitable type, and the method by which the encoder selects the values ofgeneral_progressive_source flag and general_interlaced_source_flag maybe unspecified.

In one example general_progressive_source _flag in profile_tier_levelsyntax structure in Sequence Parameter Set (SPS) and Video Parameter Set(VPS) is required to be set equal to 1. Thus it will be a requirement ofthe bitstream conformance for the coded video bitstream thatgeneral_progressive_source_flag in profile_tier syntax structure inSequence Parameter Set (SPS) and Video Parameter Set (VPS) is requiredto be set equal to value 1

In one example general_interlaced_source_flag flag in profile_tier_levelsyntax structure in Sequence Parameter Set (SPS) and Video Parameter Set(VPS) is required to be set equal to 0. Thus it is a requirement of thebitstream conformance for the coded video bitstream thatgeneral_interlaced_source_flag in profile_tier_level syntax structure inSequence Parameter Set (SPS) and Video Parameter Set (VPS) is requiredto be set equal to value 0.

general_frame_only_constraint_flag equal to 1 specifies thatfield_seq_flag is equal to 0. general_frame_only_constraint_flag equalto 0 indicates that field_seq_flag may or may not be equal to 0.

Decoders may ignore the value of general_frame_only_constraint_flag, asthere are no decoding process requirements associated with the value offield_seq_flag.

When general_progressive_source_flag is equal to 1,general_frame_only_constraint_flag may or may not be equal to 1.

In one example general_frame_only_constraint_flag in profile_tier_levelsyntax structure in Sequence Parameter Set (SPS) and Video Parameter Set(VPS) is required to be set equal to 1. Thus it is a requirement of thebitstream conformance for the coded video bitstream thatgeneral_frame_only_constraint_flag in profile_tier_level syntaxstructure in Sequence Parameter Set (SPS) and Video Parameter Set (VPS)is required to be set equal to value 1.

vui_parameters_present_flag equal to 1 may specify that thevui_parameters( ) syntax structure is present. An exemplaryvui_parameters( ) syntax structure is shown in FIG. 28. vui parameterspresent flag equal to 0 specifies that the vui parameters( ) syntaxstructure as specified in Annex E is not present.

field_seq_flag equal to 1 may indicate that the coded video sequenceconveys pictures that represent fields, and specifies that a picturetiming SEI message may be present in every access unit of the currentCVS. field_seq_flag equal to 0 may indicate that the CVS conveyspictures that represent frames and that a picture timing SEI message mayor may not be present in any access unit of the current CVS. Whenfield_seq_flag is not present, it is inferred to be equal to 0. Whengeneral_frame_only_constraint_flag is equal to 1, the value offield_seq_flag may be equal to 0.

The specified decoding process does not treat access units conveyingpictures that represent fields or frames differently. A sequence ofpictures that represent fields would therefore be coded with the picturedimensions of an individual field. For example, access units containingpictures that represent 1080i fields would commonly have cropped outputdimensions of 1920×540, while the sequence picture rate would commonlyexpress the rate of the source fields (typically between 50 and 60 Hz),instead of the source frame rate (typically between 25 and 30 Hz).

frame_field_info_present_flag equal to 1 may specify that picture timingSEI messages are present for every picture and include the pic_struct,source_scan_type, and duplicate_flag syntax elements.frame_field_info_present_flag equal to 0 may specify that the pic_structsyntax element is not present in picture timing SEI messages.

When frame_field_info_present_flag is present and either or both of thefollowing conditions are true, frame_field_info_present_flag may beequal to 1:

-   -   field_seq_flag is equal to 1.    -   general_progressive_source_flag is equal to 1 and        general_interlaced_source_flag is equal to 1.

When frame_field_info_present_flag is not present, its value is inferredas follows:

-   -   If general_progressive_source _flag is equal to 1 and        general_interlaced_source_flag is equal to 1,        frame_field_info_present_flag is inferred to be equal to 1.    -   Otherwise, frame_field_info_present_flag is inferred to be equal        to 0.

In one example: If vui_parameters_present_flag in SPS is equal to 1 thenit is required that field_seq_flag is set equal to 0 andframe_field_info_present_flag is set equal to 0. Thus it is arequirement of the bitstream conformance for the coded video bitstreamthat if vui_parameters_present_flag in SPS is equal to 1 then it isrequired that field_seq_flag is set equal to 0 andframe_field_info_present_flag is set equal to 0.

In another example: vui_parameters_present_flag in SPS is required to beset to 1 and it is required that field_seq_flag is set equal to 0 andframe_field_info_present_flag is set equal to 0. Thus it is arequirement of the bitstream conformance for the coded video bitstreamthat vui_parameters_present_flag in SPS is required to be set to 1 andit is required that field_seq_flag is set equal to 0 andframe_field_info_present_flag is set equal to 0.

vui_timing_info_present_flag equal to 1 may specify thatvui_num_units_in_tick, vui_time_scale,vui_poc_proportional_to_timing_flag, and vui_hrd_parameters_present_flagare present in the vui_parameters( ) syntax structure,vui_timing_info_present_flag equal to 0 may specify thatvui_num_units_in_tick, vui_time_scale,vui_poc_proportional_to_timing_flag, and vui_hrd_parameters_present_flagare not present in the vui_parameters( ) syntax structure.

vui_hrd_parameters_present_flag equal to 1 may specify that the syntaxstructure hrd_parameters( ) is present in the vui_parameters( ) syntaxstructure. vui_hrd_parameters_present_flag equal to 0 may specify thatthe syntax structure hrd_parameters( ) is not present in thevui_parameters( ) syntax structure.

The hrd_parameters( ) syntax structure provides hypothetical referencedecoder (HRD) parameters used in the HRD operations for a layer set.When the hrd_parameters( ) syntax structure is included in a VPS, theapplicable layer set to which the hrd_parameters( ) syntax structureapplies is specified by the corresponding hrd_layer_set_idx[i] syntaxelement in the VPS. When the hrd_parameters( ) syntax structure isincluded in an SPS, the layer set to which the hrd_parameters( ) syntaxstructure applies is the layer set for which the associated layeridentifier list contains all nuh_layer_id values present in the CVS.

fixed_pic_rate_general_flag[i] equal to 1 may indicate that, whenHighestTid is equal to the temporal distance between the HRD outputtimes of consecutive pictures in output order is constrained asspecified below. fixed_pic_rate_general_flag[i] equal to 0 may indicatethat this constraint may not apply.

When fixed_pic_rate_general_flag[i] is not present, it may be inferredto be equal to 0.

fixed_pic_rate_within_cvs_flag[i] equal to 1 may indicate that, whenHighestTid is equal to i, the temporal distance between the HRD outputtimes of consecutive pictures in output order is constrained asspecified below.

fixed_pic_rate_within_cvs_flag[i] equal to 0 may indicate that thisconstraint may not apply.

When fixed_pic_rate_general_flag[i] is equal to 1, the value of fixedpic rate within cvs flag[i] may be inferred to be equal to 1.

maxNumSubLayersMinus1 may be a parameter indicating the maximum numberof temporal sub-layers.

The variable HighestTid, which identifies the highest temporal sub-layerto be decoded, may be specified as follows:

-   -   If some external means, not specified in HEVC International        standard specification, is available to set HighestTid,        HighestTid is set by the external means.    -   Otherwise, if the decoding process is invoked in a bitstream        conformance test as specified in subclause C.1 of HEVC        International standard specification, HighestTid is set as        specified in subclause C.1 of HEVC International standard        specification.    -   Otherwise, HighestTid is set equal to sps_max_sub_layers_minus1.

sps_max_sub_layers_minus1 plus 1 may specify the maximum number oftemporal sub-layers that may be present in each CVS referring to theSPS. The value of sps_max_sub_layers_minus1 may be in the range of 0 to6, inclusive. The value of sps_max_sub_layers_minus1 may be less than orequal to vps_max_sub_layers_minus1.

vps_max_sub_layers_minus1 plus 1 may specify the maximum number oftemporal sub-layers that may be present in each CVS referring to theVPS. The value of vps_max_sub_layers_minus1 may be in the range of 0 to6, inclusive.

In one example vui_parameters_present_flag in SPS is required to be setto equal to 1, vui_timing_info_present_flag in SPS is required to be setequal to 1, vui_hrd_parameters_present_flag in SPS is required to be setequal to 1, and additionally:

-   -   In one example: fixed_pic_rate_general_flag[i] is required to be        set equal to 1 or fixed_pic_rate_within_cvs_flag[i] is required        to be set equal to 1 for all value of i in the range 0 to        maxNumSubLayersMinus1, inclusive.    -   In another example: fixed_pic_rate_general_flag[i] is required        to be set equal to 1 or fixed_pic_rate_within_cvs_flag[i] is        required to be set equal to 1 for i equal to        maxNumSubLayersMinus1.

Thus it will be a requirement of the bitstream conformance for the codedvideo bitstream that vui_parameters_present_flag in SPS is required tobe set to equal to 1, vui_timing_info_present_flag in SPS is required tobe set equal to vui_hrd_parameters_present_flag in SPS is required to beset equal to 1, and additionally:

-   -   In one example it will be a requirement of the bitstream        conformance for the coded video bitstream that        fixed_pic_rate_general_flag[i] is required to be set equal to 1        or fixed_pic_rate_within _cvs_flag[i] is required to be set        equal to 1 for all value of i in the range 0 to        maxNumSubLayersMinus1, inclusive.    -   In another example it will be a requirement of the bitstream        conformance for the coded video bitstream that        fixed-pic_rate_general_flag[i] is required to be set equal to 1        or fixed_pic_rate_within_cvs_flag[i] is required to be set equal        to 1 for i equal to maxNumSubLayersMinus1.

Following constraints are additionally proposed for SHVC coded videocarried in ATSC 3.0 video subsystem. Thus when SHVC coded video iscarried in ATSC 3.0 video subsystem all the constraints specified aboveand below are mandated.

vps_extension_flag equal to 0 may specify that no vps_extension( )syntax structure is present in the VPS RBSP syntax structure.vps_extension_flag equal to 1 may specify that the vps_extension( )syntax structure is present in the VPS RBSP syntax structure. WhenMaxLayersMinus1 is greater than 0, vps_extension_flag may be equal to 1.

vps_max_layers_minus1 plus 1 may specify the maximum allowed number oflayers in the CVS. vps_max_layers_minus1 may be less than 63 inbitstreams conforming to this version of this Specification. The valueof 63 for vps_max_layers_minus1 is reserved for future use byITU-T|ISO/IEC. Although the value of vps_max_layers_minus1 is requiredto be less than 63 in this version of this Specification, decoders mayallow a value of vps_max_layers_minus1 equal to 63 to appear in thesyntax. In a future super multiview coding extension of thisspecification, the value of 63 for vps_max_layers_minus1 will be used toindicate an extended number of layers.

The variable MaxLayersMinus1 may be set equal to Min(62,vps_max_layers_minus1). In this document the variable MaxLayersMinus1and syntax element vps_max_layers_minus1 may be used interchangeably.Both of them maybe used to denote the same thing.

In one example vps_extension_flag is required to be set equal to 1.

Thus it will be a requirement of the bitstream conformance for the codedvideo bitstream that vps_extension_flag is required to be set equal to1.

vps_num_profile_tier_level_minus1 plus 1 specifies the number ofprofile_tier_level( ) syntax structures in the VPS. The value ofvps_num_profile_tier_level_minus1 may be in the range of 0 to 63,inclusive.

profile_level_tier_idx[i] may specifies the index, into the list ofprofile_tier_level( ) syntax structures in the VPS, of theprofile_tier_level( ) syntax structure that applies to i-th output layerset. The length of the profile_level_tier_idx[i] syntax element isCeil(Log 2(vps_num_profile_tier_level_minus1+1)) bits. The value ofprofile_level_tier_idx[0] may be inferred to be equal to 0. The value ofprofile_level_tier_idx[i] may be in the range of 0 tovps_num_profile_tier_level_minus1, inclusive.

In one example if vps_num_profile_tier_level_minus1 is greater than 0then for each profile_tier_level( ) syntax structure in vps_extension( )that applies to layer set to be carried in the video subsystem of thisspecification as indicated by the profile_tier_level_idx[i]:

-   -   the value of general_progressive_source_flag is required to be        set equal to 1,    -   the value of general_interlaced_source_flag is required to be        set equal to 0 and    -   the value of general_frame_only_constraint_flag is required to        be set equal to 1.

Thus in one example it will be a requirement of the bitstreamconformance for the coded video bitstream ifvps_num_profile_tier_level_minus1 is greater than 0 then for eachprofile_tier_level( ) syntax structure in vps_extension( ) that appliesto layer set to be carried in the video subsystem of this specificationas indicated by the profile_tier_level_idx[i]:

-   -   the value of general_progressive_source_flag is required to be        set equal to 1,    -   the value of general_interlaced_source_flag is required to be        set equal to 0 and    -   the value of general_frame_only_constraint_flag is required to        be set equal to 1.

vps_vui_present_flag equal to 1 may specify that the vps_vui( ) syntaxstructure is present in the VPS. vps_vui_present_flag equal to 0 mayspecify that the vps_vui( ) syntax structure is not present in the VPS.

bit_rate_present_vps_flag equal to 1 specifics that the syntax elementbit_rate_present_flag[i][j] is present. bit_rate_present_vps_flag equalto 0 specifies that the syntax element bit_rate_present_flag[i][j] isnot present.

pic_rate_present_vps_flag equal to 1 specifies that the syntax elementpic_rate_present_flag[i][j] is present. pic_rate_present_vps_flag equalto 0 specifies that the syntax element pic_rate_present_flag[i][j] isnot present.

bit_rate_present_flag[i][j] equal to 1 specifies that the bit rateinformation for the j-th subset of the i-th layer set is present.bit_rate_present_flag[i] equal to 0 specifies that the bit rateinformation for the j-th subset of the i-th layer set is not present.The j-th subset of a layer set is the output of the sub-bitstreamextraction process when it is invoked with the layer set, j, and thelayer identifier list associated with the layer set as inputs. When notpresent, the value of bit_rate_present_flag[i][j] is inferred to beequal to 0.

pic_rate_present_flag[i][j] equal to 1 specifies that picture rateinformation for the j-th subset of the i-th layer set is present.pic_rate_present_flag[i][j] equal to 0 specifies that picture rateinformation for the j-th subset of the i-th layer set is not present.When not present, the value of pic_rate_present_flag[i][j] is inferredto be equal to 0.

avg_bit_rate[i][j] may indicate the average bit rate of the j-th subsetof the i-th layer set, in bits per second. The value is given byBitRateBPS(avg_bit_rate[i][j]) with the function BitRateBPS( ) beingspecified as follows: BitRateBPS(x)=(x & (214−1))*10(2+(x>>14))

The average bit rate is derived according to the access unit removaltime specified in clause F.13. In the following, bTotal is the number ofbits in all NAL units of the j-th subset of the i-th layer set, t1 isthe removal time (in seconds) of the first access unit to which the VPSapplies, and t2 is the removal time (in seconds) of the last access unit(in decoding order) to which the VPS applies. With x specifying thevalue of avg_bit_rate[i][j], the following applies:

-   -   If t1 is not equal to t2, the following condition may be true:        (x & (214−1))==Round(bTotal÷((t2−t1)*10(2+(x>>14))))    -   Otherwise (t1 is equal to t2), the following condition maybe        true: (x & (214−1))==0

max_bit_rate_layer[i][j] indicates an upper bound for the bit rate ofthe j-th subset of the i-th layer set in any one-second time window ofaccess unit removal time as specified in clause F.13. The upper boundfor the bit rate in hits per second is given byBitRateBPS(max_bit_rate_layer[i][j]). The bit rate values are derivedaccording to the access unit removal time specified in clause F.13. Inthe following, t1 is any point in time (in seconds), t2 is set equal tot1+1÷100, and bTotal is the number of bits in all NAL units of accessunits with a removal time greater than or equal to t1 and less than t2.With x specifying the value of max_bit_rate_layer[i][j], the followingcondition may be obeyed for all values of t1: (x &(214−1))>=bTotal÷((t2−t1)*10(2+(x>>14)))

constant_pic_rate_idc[i][j] may indicate whether the picture rate of thej-th subset of the i-th layer set is constant. In the following, atemporal segment tSeg is any set of two or more consecutive accessunits, in decoding order, of the j-th subset of the i-th layer set,auTotal(tSeg) is the number of access units in the temporal segmenttSeg, t1(tSeg) is the removal time (in seconds) of the first access unit(in decoding order) of the temporal segment tSeg, t2(tSeg) is theremoval time (in seconds) of the last access unit (in decoding order) ofthe temporal segment tSeg, and avgPicRate(tSeg) is the average picturerate in the temporal segment tSeg, and is specified as follows:

avgPicRate(tSeg)==Round(auTotal(tSeg)*256÷(t2(tSeg)−t1(tSeg)))

If the j-th subset of the i-th layer set only contains one or two accessunits or the value of avgPicRate(tSeg) is constant over all the temporalsegments, the picture rate is constant; otherwise, the picture rate isnot constant.

constant_pic_rate_idc[i][j] equal to 0 may indicate that the picturerate or the j-th subset of the i-th layer set is not constant.constant_pic_rate_idc[i][j] equal to 1 indicates that the picture rateof the j-th subset of the i-th layer set is constant.constant_pic_rate_idc[i][j] equal to 2 indicates that the picture rateof the j-th subset of the i-th layer set may or may not be constant. Thevalue of constant_pic_rate_idc[i][j] may be in the range of 0 to 2,inclusive.

avg_pic_rate[i] may indicate the average picture rate, in units ofpicture per 256 seconds, of the j-th subset of the layer set. WithauTotal being the number of access units in the j-th subset of the i-thlayer set, t1 being the removal time (in seconds) of the first accessunit to which the VPS applies, and t2 being the removal time (inseconds) of the last access unit (in decoding order) to which the VPSapplies, the following applies:

-   -   If t1 is not equal to t2, the following condition may be true:        avg_pic_rate[i]==Round(auTotal*256÷(t2−t1))    -   Otherwise (t1 is equal to t2), the following condition may be        true: avg_pic_rate[i]==0

In another example the avg_bit_rate[i][j] and avg_pic_rate[i] may bedefined differently that above while still indicating average bit rateand average picture rate (i.e. average frame rate).

In one example: if vps_vui_present _flag in VPS is equal to 1,pic_rate_present_vps_flag is equal to 1 and pic_rate_present_flag[i][j]is equal to 1 then it is required that constant_pic_rate_idc[i][j] isset equal to 1.

In another example: It is required that vps_vui_present_flag in VPS isset equal to 1, pic_rate_present_vps_flag is set equal to 1,pic_rate_present_flag[i][j] is set equal to 1 andconstant_pic_rate_idc[i][j] is set equal to 1 for all i, for all j. Inanother example: It is required that vps_vui_present_flag in VPS is setequal to 1, pic_rate_present_vps_flag is set equal to 1,pic_rate_present_flag[i][j] is set equal to 1 andconstant_pic_rate_idc[i][j] is set equal to 1 for all i, correspondingto the layer set to be carried in the video subsystem of thisspecification for j equal to the maximum value of the temporalsub-layers to be carried in the video subsystem of specification. In oneexample If vps_num_hrd_parameters is greater than 0 then for eachhrd_parameters( ) syntax structure in VPS that applies to layer set tobe carried in the video subsystem of this specification:

-   -   in one variant in hrd_parameters( ) syntax structure in VPS:        fixed_pic_rate_general_flag[i] is required to be set equal to 1        or fixed_pic_rate_within_cvs_flag[i] is required to be set equal        to 1 for all value of i in the range 0 to maxNumSubLayersMinus1,        inclusive.    -   in another variant in hrd_parameters( ) syntax structure in VPS:        fixed_pic_rate_general_flag[i] is required to be set equal to 1        or fixed_pic_rate_within_cvs_flag[i] is required to be set equal        to 1 for i equal maxNumSubLayersMinus1.

In one example for the layer set to be carried in the video subsystem ofthis specification the list of allowed values for avg_pic_rate[i][j] maybe restricted to: 24*256, 30*256, 60*256, 120*256, (24/1.001)*256,(30/1.001)*256, (60/1.001)*256, (120/1.001)*256. Thus in one example itwill be a requirement of the bitstream conformance for the coded videobitstream that for the layer set to be carried in the video subsystem ofthis specification the list of allowed values for avg_pic_rate[i][j] maybe restricted to: 24*256, 30*256, 60*256 120*256, (24/1.001)*256,(30/1.001)*256, (60/1.001)*256, (120/1.001)*256.

In one example it is required that if an access unit includes a picturewith nuh_layer_id>0 then it is required to include a picture withnuh_layer_id equal to 0. Thus in one example it will be a requirement ofthe bitstream conformance for the coded video bitstream that if anaccess unit includes a picture with nuh_layer_id>0 then it is requiredto include a picture with nuh_layer_id equal to 0.

In one example the syntax element elemental_duration_in_tc_minus1[i] inhrd_parameters( ) syntax structure in VPS corresponding to the layer setto be carried in the video subsystem of this specification is requiredto have the same value as the value of the syntax elementelemental_duration_in_tc_minus1[i] in the hrd_parameters( ) syntaxstructure in SPS for each i.

Thus in one example it will be a requirement of the bitstreamconformance for the coded video bitstream that the syntax elementelemental_duration_in_tc_minus1[i] in hrd_parameters( ) syntax structurein VPS corresponding to the layer set to be carried in the videosubsystem of this specification is required to have the same value asthe value of the syntax element elemental_duration_in_tc_minus1[i] inthe hrd_parameters( ) syntax structure in SPS for each i.

In another example the syntax element elemental_duration_in_tc_minus1[i]in hrd_parameters( ) syntax structure in VPS applicable to each layer isrequired to have the same value for each layer.

Thus in one example it will be a requirement of the bitstreamconformance for the coded video bitstream that the syntax elementelemental_duration__in_tc_minus1[i] in hrd_parameters( ) syntaxstructure in VPS applicable to each layer is required to have the samevalue for each layer.

elemental_duration_in_tc_minus1[i] plus 1 (when present) may specify,when HighestTid is equal to i, the temporal distance, in clock ticks,between the elemental units that specify the HRD output times ofconsecutive pictures in output order as specified below. The value ofelemental_duration_in_tc_minus1[i] may be in the range of 0 to 2047,inclusive.

For each picture n that is output and not the last picture in thebitstream (in output order) that is output, the value of the variableDpbOutputElementalInterval[n] is specified by:DpbOutputElementalInterval[n]=DpbOutputInterval[n] DeltaToDivisor, whereDpbOutputInterval[n] is specified in Equation C 17 in HEVC specificationand DeltaToDivisor is specified in Table X based on the value offrame_field_info_present_flag and pic_struct for the CVS containingpicture n. Entries marked “-” in Table X indicate a lack of dependenceof DeltaToDivisor on the corresponding syntax element.

When HighestTid is equal to i and fixed_pic_rate_general_flag[i] isequal to 1 for a CVS containing picture n, the value computed forDpbOutputElementalInterval[n] may be equal toClockTick*(elemental_duration_in_tc_minus1[i]+1), wherein ClockTick isas specified in Equation C 2 in HEVC specification (using the value ofClockTick for the CVS containing picture n) when one of the followingconditions is true for the following picture in output ordernextPicInOutputOrder that is specified for use in Equation C 17 in HEVCspecification:

-   -   picture nextPicInOutputOrder is in the same CVS as picture n.    -   picture nextPicInOutputOrder is in a different CVS and        fixed_pic_rate_general_flag[i] is equal to 1 in the CVS        containing picture nextPicInOutputOrder, the value of ClockTick        is the same for both CVSs, and the value of        elemental_duration_in_tc_minus1[i] is the same for both CVSs.

When HighestTid is equal to i and fixed_pic_rate_within_cvs_flag[i] isequal to 1 for a CVS containing picture n, the value computed forDpbOutputElementalInterval[n] may be equal toClockTick((elemental_duration_in_tc_minus1[i]+1), wherein ClockTick isas specified in Equation C 2 in HEVC specification (using the value ofClockTick for the CVS containing picture n) when the following picturein output order nextPicInOutputOrder that is specified for use inEquation C 17 in HEVC specification is in the same CVS as picture n.

TABLE X Divisor for computation of DpbOutputElementalInterval[n]frame_field_info_present_flag pic_struct DeltaToDivisor 0 — 1 1 1 1 1 21 1 0 1 1 3 2 1 4 2 1 5 3 1 6 3 1 7 2 1 8 3 1 9 1 1 10 1 1 11 1 1 12 1

Additional description is now provided regarding constraints related totemporal sub-layers.

HEVC may define temporal sub-layer as follows:

A temporal scalable layer of a temporal scalable bitstream, consistingof VCL NAL units with a particular value of the TemporalId variable andthe associated non-VCL NAL units. Also the term sub-layer may be usedfor temporal sub-layer.

Specific constraints are described next regarding the use of temporalsub-layering. Although the description below uses words “temporalsub-layer” instead words “temporal layer” may be used to describe theseconstraints. Similarly although the description below uses words“temporal sub-layering” instead words “temporal layering” may be used todescribe these constraints.

In an example, when an HEVC Main 10 Profile or HEVC Scalable Main 10Profile bitstream has a constant picture rate (as indicated by thepresence of elemental_duration_in_tc_minus1[ ]) equal to 120, 120/1.001,or 100 pictures per second (as specified byelemental_duration_in_tc_minus1[ ]), temporal sub-layering with twotemporal sub-layers may be applied; otherwise all the pictures may haveTemporalID equal to 0.

In another example it may be required that otherwise all the picturesmay have same value of nuh_temporal_id_plus1 (or same value ofTemporalID). It may be required that when temporal sub-layering with twotemporal sub-layers is applied, the bitstream may comply with thefollowing constraints:

-   -   The bitstream may contain exactly two sub-layers, with        TemporalId equal to 0 and 1, respectively, and the value of        sps_max_sub_layers_minus1 of each SPS may be set equal to 1 and        value of vps_max_sub_layers_minus1 of each VPS may be set equal        to 1. Signaling the vps_max_sub_layers_minus1 value equal to 1        in each VPS allows a receiver entity that the stream will never        have more than 2 temporal sub-layers. In this case it does not        need to parse each SPS to find out how many maximum number of        temporal sub-layers may be present.    -   The sub-layer representation with TemporalId equal to 0 may have        a constant picture rate (as indicated by the presence of        elemental_duration_in_tc_minus1[0]), and the picture rate may be        exactly half of that of the entire bitstream (i.e.,        elemental_duration_in_tc_minus1[0] is equal to        2*elemental_duration_in_tc_minus1[1]). This constraint allows        use of only temporal sub-layer zero while providing constant        picture rate which can provide better user experience.    -   The value of sub_layer_profile_present_flag[0] may be equal        to 1. This constraint requires the signaling of the profile        related fields of the sub-layer representation with TemporalId        equal to 0.    -   In profile_tier_level( ) in each SPS, the value of        sub_layer_level_present_flag[0] may be equal to 1 only when the        value of sub_layer_level_idc[0] is different than the value of        general_level_idc. This constraint requires signaling of the        level of the sub-layer representation with TemporalId equal to 0        only when that level is different than the level of the overall        bitstream. The overall bitstream may be the bitstream consisting        of temporal sub-layer with TemporalID equal to 0 and temporal        sub-layer with TemporalID equal to 1.

In another example, the following constraint may be required: The valueof sub_layer_level_present_flag[0] in profile_tier_level( ) in each SPSand first profile_tier_level( ) in VPS may be equal to 1. Thisconstraint requires the signaling of the Level of the sub-layerrepresentation with TemporalId equal to 0.

In yet another variation the following constraint may be required: Ineach SPS and first profile_tier_level( ) in VPS the value ofsub_layer_level_present_flag[0] in profile_tier_level( ) may be equal to1 only when the value of sub_layer_level_idc[0] is different than thevalue of general_level _idc. This constraint requires signaling of thelevel of the sub-layer representation with TemporalId equal to 0 onlywhen that level is different than the level of the overall bitstream.The overall bitstream may be the bitstream consisting of temporalsub-layer with TemporalID equal to 0 and temporal sub-layer withTemporalID equal to 1.

Additional variations of the constraint are described further asfollows:

-   -   It may be required that the profile_tier_level( ) in each SPS,        the value of sub_layer_level_present_flag[0] may be equal to 1        when the value of sub_layer_level_idc[0] is different than the        value of general_level_idc. This constraint requires the        signaling of the Level of the sub-layer representation with        TemporalID equal to 0.    -   Alternatively, it may be required that in each SPS and first        profile_tier_level( ) in VPS the value of        sub_layer_level_present_flag[0] in profile_tier_level( ) may be        equal to 1 when the value of sub_layer_level_idc[0] is different        than the value of general_level_idc. This constraint requires        the signaling of the Level of the sub-layer representation with        TemporalId equal to 0.

In other variation of the constraint an encoder and/or decoder may applya constraint on all profile_tier_level structures signaled in thebitstream. These constraints are described further as follows:

-   -   It may be required that the value of        sub_layer_level_present_flag[0] may be equal to 1 only when the        value of sub_layer_level_idc[0] is different than the value of        general_level_idc. This constraint requires signaling of the        level of the sub-layer representation with TemporalId equal to 0        only when that level is different than the level of the overall        bitstream. The overall bitstream may be the bitstream consisting        of temporal sub-layer with TemporalID equal to 0 and temporal        sub-layer with TemporalID equal to 1.    -   Alternatively: It may be required that the value of        sub_layer_level_present_flag[0] in profile_tier_level( ) may be        equal to 1 only when the value of sub_layer_level_idc[0] is        different than the value of general_level_idc. This constraint        requires signaling of the level of the sub-layer representation        with TemporalId equal to 0 only when that level is different        than the level of the overall bitstream. The overall bitstream        may be the bitstream consisting of temporal sub-layer with        TemporalID equal to 0 and temporal sub-layer with TemporalID        equal to 1.

When temporal sub-layering with two temporal sub-layers is applied tothe base layer and an enhancement layer exists, the enhancement layermay have the same picture rate as the picture rate of the base layer,and temporal sub-layering with two temporal sub-layers may be applied tothe enhancement layer with the same constraints as the base layer.

It may be required that when temporal sub-layering with two temporalsub-layers is not applied to the base layer, all the pictures of theenhancement layer may have TemporalID equal to 0.

In a different example it may be required that when temporalsub-layering with two temporal sub-layers is not applied to the baselayer, all the pictures of the enhancement layer may have the same valueof nuh_temporal_id_plus1 (i.e. same value of TemporalID).

It is to be understood that any of the features, whether indicated asshall or necessary or otherwise, may be omitted as desired. In addition,the features may be combined in different combinations, as desired.

In an example Dynamic Adaptive Streaming over HTTP (DASH) specified inISO/IEC FDIS 23009-1:2014 (which is incorporated by reference herein inits entirety) may be used for streaming media content. DASH is a systemfor streaming content, services, and/or other media using the HypertextTransfer Protocol (HTTP). The system includes formats for the MediaPresentation Description and Segments. In an example, DASH may be usedfor streaming services content, services, and/or other media over theInternet.

Additional description is now provided regarding signaling the temporalsub-layer related parameters. In one example these temporal sub-layersrelated parameters may be signaled in a descriptor. In one example thedescriptor may be included in a DASH based streaming system.

DASH MPD or MPD (e.g. MPD element) is a formalized description for aMedia Presentation for the purpose of providing a streaming service.

DASH Media Presentation or Media Presentation is a collection of datathat establishes a bounded or unbounded presentation of media content.

DASH Period or Period (e.g. Period element) is an interval of the MediaPresentation, where a contiguous sequence of all Periods constitutes theMedia Presentation.

DASH Adaptation Set or Adaptation Set (e.g. AdaptationSet element) is aset of interchangeable encoded versions of one or several media contentcomponents.

DASH Representation or Representation (e.g. Representation element) is acollection and encapsulation of one or more media streams in a deliveryformat and associated with descriptive metadata.

In one example a descriptor for providing temporal sub-layer relatedinformation may be signaled in a DASH MPD.

In one example: when Temporal Sub-layering with constraints definedabove is used in a Representation, then a Supplemental Descriptor may bepresent at that Representation, with @schemeIdUri oftag:atsc.org,2016:temporallayering URI. The value of the @valueattribute may contain value of syntax element sub_layer_level_idc[0] forthe Representation which will indicate the Level for temporal sub-layerzero.

If all Representations of an Adaptation Set contain TemporalSub-layering with constraints defined above and all Representations havethe same Level (i.e. same value for sub_layer_level_idc[0]) for temporalsub-layer zero, then the above descriptor may be used at the AdaptationSet element.

It should be noted that some other name may be used for the @schemeIdUrisuch as “tag:atsc.org,2016:temporalsub-layering” or“tag:atsc.org,2016:sub-layering”

A few additional variant examples for signaling temporal sub-layerparameters information in the descriptor are described next.

In one example when Temporal Sub-Layering with constraints defined aboveis used in a Representation, then a Supplemental Descriptor may bepresent at that Representation, with @schemeIdUri oftag:atsc.org,2016:temporallayering URI. The value of the @valueattribute may consist of two parts separated by a delimiter ‘,’ withsecond part optionally present.

The first part will have value with meanings defined as follows:

“1” which indicates the bitstream contains exactly two temporalsub-layers with temporal id values 0 and 1

“0” which indicates only one temporal sub-layer is present in thebitstream.

Other values are unspecified and may be reserved for future use.

When the first part is equal to “1”, the second part will signal valueequal to value of syntax element sub_layer_level_idc[0] for theRepresentation which will indicate the Level for temporal sub-layerzero.

If all Representations of an Adaptation Set contain Temporal Layeringwith constraints defined above and all Representations have the sameLevel for temporal sub-layer zero, then the above descriptor may be usedat the Adaptation Set element.

In this example instead of the delimiter ‘,’ some other delimiter suchas ‘SPACE’ or ‘;’ or ‘:’ or some other delimiter may be used.

In one example when Temporal Sub-Layering with constraints defined aboveis used in a Representation, then a Supplemental Descriptor may bepresent at that Representation, with @schemeIdUri oftag:atsc.org,2016:temporallayering URI. The value of the @valueattribute may contain value coded as a string using process defined forCodecs MIME type specification in Annex E section E.3 of ISO/IEC14496-15 for single layer HEVC with syntax clementsub_layer_profile_space[0], sub_layer_tier_flag[0],sub_layer_profile_idc[0], sub layer profile compatibility flag[0[j] forj in the range of 0 to 31, inclusive, and each of 6 bytes of theconstraint flags starting from sub_layer_progressive_source_flag[0]respectively substituted for element general_profile_space,general_tier_flag, general_profile_idc,general_profile_compatibility_flag[j] for j in the range of 0 to 31,inclusive, and each of 6 bytes of the constraint flags starting fromgeneral_progressive_source_flag.

ISO/IEC 14496-15 is incorporated here in by reference.

If all Representations of an Adaptation Set contain TemporalSub-Layering with constraints defined above and all Representations havethe same Level for temporal sub-layer zero, then the above descriptormay be used at the Adaptation Set element.

In yet another example when Temporal Sub-Layering with constraintsdefined in above is used in a Representation, then a SupplementalDescriptor may be present at that Representation, with @schemeIdUri oftag:atsc.org,2016:temporallayering URI. The value of the @valueattribute may consist of two parts separated by a delimiter ‘,’ withsecond part optionally present:

The first part will be an 8-bit unsigned integer with value equal to theLevel for temporal sub-layer zero of the Representation. This will beequal to the value of syntax element sub_layer_level_idc[0] of theRepresentation.

The second part if present will be coded as a string using processdefined for Codecs MIME type specification in Annex E section E.3 ofISO/IEC 14496-15 for single layer HEVC with syntax elementsub_layer_profile_space[0], sub_layer_tier_flag[0],sub_layer_profile_idc[0], sub_layer_profile_compatibility_flag[0][j] forj in the range of 0 to 31, inclusive, and each of 6 bytes of theconstraint flags starting from sub_layer_progressive_source_flag[0]respectively substituted for element general_profile_space,general_tier_flag, general_profile_idc,general_profile_compatibility_flag[j] for j in the range of 0 to 31,inclusive, and each of 6 bytes of the constraint flags starting fromgeneral_progressive_source_flag. If the second part of @value is absentthen all other profile_tier_level( ) parameters for the temporalsub-layer zero besides the sub_layer_idc[0] parameter which is signaledin the first part may be inferred to be same as the value of thoseparameters signaled in Codecs parameter for the Representation. TheCodecs parameter is described in Annex E of ISO/IEC 14496-15.

If all Representations of an Adaptation Set contain TemporalSub-Layering with constraints defined above and all Representations havethe same profile, tier, level and flags information for temporalsub-layer zero, then the above descriptor may be used at the AdaptationSet element.

In the text above the term “with constraints defined above” may insteadbe replaced with or equivalent to all or part of the term “with temporalsub-layering related constraints defined in ATSC 3.0 HEVC Video standardA/341”. The ATSC 3.0 standard A/341 is incorporated here in byreference.

The term “computer-readable medium” refers to any available medium thatcan be accessed by a computer or a processor. The term“computer-readable medium,” as used herein, may denote a computer-and/or processor-readable medium that is non-transitory and tangible. Byway of example, and not limitation, a computer-readable orprocessor-readable medium may comprise RAM, ROM, EEPROM, CD-ROM or otheroptical disk storage, magnetic disk storage or other magnetic storagedevices, or any other medium that can be used to carry or store desiredprogram code in the form of instructions or data structures and that canbe accessed by a computer or processor. Disk and disc, as used herein,includes compact disc (CD), laser disc, optical disc, digital versatiledisc (DVD), floppy disk and Blu-ray (Registered Trademark) disc wheredisks usually reproduce data magnetically, while discs reproduce dataoptically with lasers.

It should be noted that one or more of the methods described herein maybe implemented in and/or performed using hardware. For example, one ormore of the methods or approaches described herein may be implemented inand/or realized using a chipset, an ASIC, a large-scale integratedcircuit (LSI) or integrated circuit, etc.

Each of the methods disclosed herein comprises one or more steps oractions for achieving the described method. The method steps and/oractions may be interchanged with one another and/or combined into asingle step without departing from the scope of the claims. In otherwords, unless a specific order of steps or actions is required forproper operation of the method that is being described, the order and/oruse of specific steps and/or actions may be modified without departingfrom the scope of the claims.

Moreover, each functional block or various features of the base stationdevice and the terminal device (the video decoder and the video encoder)used in each of the aforementioned embodiments may be implemented orexecuted by a circuitry, which is typically an integrated circuit or aplurality of integrated circuits. The circuitry designed to execute thefunctions described in the present specification may comprise ageneral-purpose processor, a digital signal processor (DSP), anapplication specific or general application integrated circuit (ASIC), afield programmable gate array (FPGA), or other programmable logicdevices, discrete gates or transistor logic, or a discrete hardwarecomponent, or a combination thereof. The general-purpose processor maybe a microprocessor, or alternatively, the processor may be aconventional processor, a controller, a microcontroller or a statemachine. The general-purpose processor or each circuit described abovemay be configured by a digital circuit or may be configured by ananalogue circuit. Further, when a technology of making into anintegrated circuit superseding integrated circuits at the present timeappears due to advancement of a semiconductor technology, the integratedcircuit by this technology is also able to be used.

It is to be understood that the claims are not limited to the preciseconfiguration and components illustrated above. Various modifications,changes and variations may be made in the arrangement, operation anddetails of the systems, methods, and apparatus described herein withoutdeparting from the scope of the claims.

1. A method for decoding a video bitstream comprising the steps of: (a)receiving said video bitstream that includes a plurality of temporalsub-layers; (b) receiving a value of a value attribute associated withone of the plurality of temporal sub-layers where said value includes afirst part and a second part separated by a delimiter; (c) decoding saidbitstream based upon said value attribute, (d) wherein said first partis an 8-bit unsigned integer with a value equal to a level for temporalsub-layer zero of a representation, (e) wherein said second part is,alternatively, (i) if said second part is present then said second partis coded as string of a single layer video encoding with a syntaxelement based upon a sub layer profile space, a sub layer tier flag, asub layer profile idc, sub layer profile compatibility flag[0][j] for jin the range of 0 to 31, inclusive, and each of 6 bytes of constraintflags starting from a sub layer progressive source flag respectivelysubstituted for an element general profile space, a general tier flag, ageneral profile idc, a general profile compatibility flag[j] for j inthe range of 0 to 31, inclusive, and each of 6 bytes of constraint flagsstarting from a general progressive source flag, (ii) if said secondpart is absent then all other profile tier level parameters for saidtemporal sub-layer zero besides a sub layer level idc[0] parameter whichis signaled in said first part are inferred to be same as the value ofthose parameters signaled in codecs parameter for the representation,(f) wherein if all representations of an adaptation element containtemporal sub-layering with the same profile tier, level, and flagsinformation for said temporal sub-layer zero, then at least one of saidfirst part and said second part may be used for said adaptation element,and (g) wherein said level is equal to the value of a syntax element sublayer level idc[0].